Mouthwatering Rhubarb Layer Cake

I didn’t grow up eating rhubarb. My mom wasn’t really into baking with it, and honestly, I thought it looked like weird celery for most of my childhood. It wasn’t until I moved to Portland that I started seeing it everywhere in the spring—at farmers markets, in my neighbor’s garden, piled up at the grocery store.

The first time I baked with rhubarb, I made the mistake of tasting it raw. Big mistake. It’s so tart it’ll make your face scrunch up. But here’s the thing—when you cook it down with sugar and pair it with something sweet like raspberries, it becomes this perfect balance of tart and sweet. This layer cake does exactly that, with a raspberry-rhubarb filling between soft vanilla cake layers and a smooth buttercream on top. It’s become my go-to spring dessert.

What Kind of Rhubarb Should I Use?

Fresh rhubarb is definitely your best bet for this cake, and you’ll find it in season during spring and early summer at most grocery stores and farmers markets. The stalks can range from green to deep red, and while the red varieties look prettier, the color doesn’t actually affect the flavor much – both work equally well. When selecting rhubarb, look for firm, crisp stalks and avoid any that feel soft or look shriveled. If fresh rhubarb isn’t available, you can use frozen rhubarb in a pinch, just make sure to thaw it completely and drain off any excess liquid before adding it to your recipe so your cake doesn’t end up too soggy.

Options for Substitutions

This cake is pretty forgiving when it comes to swaps, so here are some options if you need them:

• Rhubarb: Fresh rhubarb is best here, but if it’s out of season, you can use frozen rhubarb – just thaw it completely and drain any excess liquid before using. You could also swap it entirely for strawberries or more raspberries for a different fruit flavor.
• Raspberries: Frozen raspberries work just as well as fresh. You can also use strawberries, blueberries, or blackberries instead.
• Sour cream: Greek yogurt makes a great substitute and gives the same moist texture. Use the same amount and make sure it’s full-fat for best results.
• Canola oil: Any neutral oil works here – vegetable oil, sunflower oil, or even melted coconut oil if you don’t mind a slight coconut flavor.
• Raspberry jam: Feel free to use strawberry, mixed berry, or even apricot jam depending on what you have in your pantry. Just make sure it’s a smooth jam rather than one with large fruit chunks for easier spreading.
• Butter in frosting: The butter in the frosting is essential for that smooth, creamy texture – don’t substitute this one or you’ll end up with a completely different consistency.

Watch Out for These Mistakes While Baking

The biggest mistake when making layer cakes is trying to frost warm cake layers, which will cause your buttercream to melt and slide right off – always let your cakes cool completely before assembling, and pop them in the fridge for 15-20 minutes if you’re in a hurry. When making Swiss meringue buttercream, adding the butter too quickly or when the meringue is still warm will result in a soupy, separated mess, so be patient and add it gradually once the bowl feels cool to the touch. If your buttercream does break and looks curdled, don’t panic – just keep beating it on medium speed for a few more minutes and it should come back together. For cleaner layers and easier frosting, try using a serrated knife to level the tops of your cakes before stacking, and apply a thin crumb coat first to lock in any loose crumbs before adding the final layer of buttercream.

What to Serve With Rhubarb Layer Cake?

This cake is pretty rich and sweet on its own, so I like to keep things simple and serve it with a dollop of lightly sweetened whipped cream or a scoop of vanilla ice cream. A hot cup of coffee or tea is perfect alongside a slice, especially if you’re serving it for an afternoon gathering or after dinner. If you want to dress it up a bit, fresh berries on the side add a nice pop of color and a tart contrast to the sweet frosting. You could also serve it with a glass of cold milk if you’re going for that classic cake-and-milk combo.

Storage Instructions

Store: Keep your rhubarb layer cake covered at room temperature for up to 2 days, or in the fridge for up to 5 days. The buttercream frosting holds up really well in the fridge, though you might want to let it sit out for about 30 minutes before serving so it’s not too firm.

Freeze: This cake freezes great for up to 3 months. I like to freeze individual slices wrapped in plastic wrap and then placed in a freezer bag, so I can grab just one piece whenever a craving hits. You can also freeze the whole cake, just make sure it’s well wrapped.

Serve: Let frozen slices thaw in the fridge overnight or at room temperature for a couple hours. The texture stays moist and the frosting comes back to its creamy consistency once it warms up a bit.

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 4300-4700
• Protein: 45-55 g
• Fat: 180-210 g
• Carbohydrates: 625-675 g

Ingredients

For the jam:

• 3/4 cup raspberries (I use Driscoll’s for consistent sweetness)
• 1 1/4 cups rhubarb (cut into 1/2-inch pieces)
• 3/4 cup sugar
• 1 tbsp lemon juice
• 1/2 tsp vanilla
• 1 pinch salt

For the cake:

• 2 1/4 cups flour (I always use King Arthur all-purpose flour)
• 1 tbsp baking powder
• 1/2 tsp salt
• 1/4 tsp ground cinnamon
• 1/4 cup butter (room temperature, about 70°F)
• 1/2 cup canola oil
• 1 1/2 cups sugar
• 3 eggs
• 1 cup sour cream (full-fat gives better texture and moisture)
• 1 1/2 tbsp vanilla
• 3/4 cup milk

For the buttercream:

• 4 egg whites
• 1 cup sugar
• 1 1/4 cups butter (I like Kerrygold unsalted butter for this)
• 1 1/2 tsp vanilla
• 1/2 cup raspberry jam (strained to remove seeds for a smoother finish)

Step 1: Prepare the Rhubarb-Raspberry Compote

• 1 1/4 cups rhubarb
• 3/4 cup raspberries
• 3/4 cup sugar
• 1 tbsp lemon juice
• 1/2 tsp vanilla
• 1 pinch salt

Combine the rhubarb pieces, raspberries, sugar, lemon juice, vanilla, and pinch of salt in a saucepan over medium heat.

Stir occasionally until the rhubarb breaks down and the mixture becomes jam-like, about 15-20 minutes.

The fruit should be very soft and syrupy.

Remove from heat and let cool completely—this will be used both as a cake layer and folded into the buttercream.

I find that straining out the raspberry seeds at this point (as with the jam) creates a smoother, more elegant filling, though it’s optional.

Step 2: Mix Dry Ingredients and Prepare Cake Batter

• 2 1/4 cups flour
• 1 tbsp baking powder
• 1/2 tsp salt
• 1/4 tsp ground cinnamon
• 1/4 cup butter
• 1/2 cup canola oil
• 1 1/2 cups sugar
• 3 eggs
• 1 cup sour cream
• 1 1/2 tbsp vanilla
• 3/4 cup milk

Preheat your oven to 350°F.

In a medium bowl, whisk together the flour, baking powder, salt, and cinnamon—this ensures even distribution of the leavening agent and spice.

In a large bowl, beat the room-temperature butter and canola oil together until combined, then add the sugar and beat until light and fluffy, about 2-3 minutes.

Add eggs one at a time, beating well after each addition to incorporate air into the batter.

Alternate adding the dry ingredient mixture and sour cream (mixed with 1 1/2 tbsp vanilla and 3/4 cup milk) in three additions each, starting and ending with dry ingredients.

Mix on low speed just until combined to avoid overworking the batter.

Step 3: Bake the Cake Layers

• cake batter from Step 2

Divide the batter evenly between two greased 6-inch round cake pans (or use one pan and bake in two batches).

Bake at 350°F for 25-30 minutes, until a toothpick inserted in the center comes out clean and the tops spring back when lightly touched.

Remove from the oven and let cool in the pans for 10 minutes, then turn out onto wire racks to cool completely.

This cooling step is crucial—a warm cake will melt the buttercream and make layering difficult.

Step 4: Make the Swiss Meringue Buttercream

• 4 egg whites
• 1 cup sugar

Create a double boiler by placing a heatproof bowl over a pot of gently simmering water (the bowl shouldn’t touch the water).

Add the egg whites and 1 cup sugar to the bowl, whisking constantly for 5-10 minutes until the mixture reaches 160°F on an instant-read thermometer and feels completely smooth with no grittiness—this pasteurizes the eggs and dissolves the sugar.

Transfer to an electric mixer and beat on high speed for 7-10 minutes until thick, glossy, and cooled to room temperature.

The mixture should hold stiff peaks.

Step 5: Build the Buttercream and Add Flavor

• 1 1/4 cups butter
• 1 1/2 tsp vanilla
• rhubarb-raspberry compote from Step 1
• 1/2 cup raspberry jam

With the mixer on medium-low speed, add the softened butter 2 tablespoons at a time, allowing each addition to incorporate fully before adding the next (this may take 5-7 minutes total).

Once all butter is incorporated, add the vanilla and beat briefly to combine.

Gently fold in the cooled rhubarb-raspberry compote from Step 1 and the strained raspberry jam, using a spatula to fold just until marbled throughout—don’t overmix or you’ll lose the pretty swirl.

I like to leave some jam visible rather than fully incorporate it, which keeps pockets of intense fruit flavor and a beautiful presentation.

Step 6: Assemble and Frost the Cake

• cooled cake layers from Step 3
• fruit-swirled buttercream from Step 5

Place the first cooled cake layer on a cake board or serving plate and spread a thin layer of the fruit-swirled buttercream from Step 5 on top.

Add another thin layer of buttercream, then add the second cake layer and press gently.

Chill the assembled cake for 30 minutes in the refrigerator—this firms up the filling and makes frosting the exterior cleaner and easier.

Remove from the fridge and frost the top and sides with the remaining buttercream, using an offset spatula for a smooth finish or creating decorative swirls as desired.

Chill for at least 30 minutes before serving so the frosting sets properly.

Mouthwatering Rhubarb Layer Cake

Delicious Mouthwatering Rhubarb Layer Cake recipe with step-by-step instructions.

Print Recipe Pin Recipe

Prep Time 50 minutes mins

Cook Time 1 hour hr 45 minutes mins

Total Time 2 hours hrs 37 minutes mins

Servings: 8 slices

Calories: 4500

Ingredients Method

Ingredients

  

For the jam

• 3/4 cup raspberries (I use Driscoll's for consistent sweetness)
• 1 1/4 cups rhubarb (cut into 1/2-inch pieces)
• 3/4 cup sugar
• 1 tbsp lemon juice
• 1/2 tsp vanilla
• 1 pinch salt

For the cake

• 2 1/4 cups flour (I always use King Arthur all-purpose flour)
• 1 tbsp baking powder
• 1/2 tsp salt
• 1/4 tsp ground cinnamon
• 1/4 cup butter (room temperature, about 70°F)
• 1/2 cup canola oil
• 1 1/2 cups sugar
• 3 eggs
• 1 cup sour cream (full-fat gives better texture and moisture)
• 1 1/2 tbsp vanilla
• 3/4 cup milk

For the buttercream

• 4 egg whites
• 1 cup sugar
• 1 1/4 cups butter (I like Kerrygold unsalted butter for this)
• 1 1/2 tsp vanilla
• 1/2 cup raspberry jam (strained to remove seeds for a smoother finish)

Method

 

1. Combine the rhubarb pieces, raspberries, sugar, lemon juice, vanilla, and pinch of salt in a saucepan over medium heat. Stir occasionally until the rhubarb breaks down and the mixture becomes jam-like, about 15-20 minutes. The fruit should be very soft and syrupy. Remove from heat and let cool completely—this will be used both as a cake layer and folded into the buttercream. I find that straining out the raspberry seeds at this point (as with the jam) creates a smoother, more elegant filling, though it's optional.
2. Preheat your oven to 350°F. In a medium bowl, whisk together the flour, baking powder, salt, and cinnamon—this ensures even distribution of the leavening agent and spice. In a large bowl, beat the room-temperature butter and canola oil together until combined, then add the sugar and beat until light and fluffy, about 2-3 minutes. Add eggs one at a time, beating well after each addition to incorporate air into the batter. Alternate adding the dry ingredient mixture and sour cream (mixed with 1 1/2 tbsp vanilla and 3/4 cup milk) in three additions each, starting and ending with dry ingredients. Mix on low speed just until combined to avoid overworking the batter.
3. Divide the batter evenly between two greased 6-inch round cake pans (or use one pan and bake in two batches). Bake at 350°F for 25-30 minutes, until a toothpick inserted in the center comes out clean and the tops spring back when lightly touched. Remove from the oven and let cool in the pans for 10 minutes, then turn out onto wire racks to cool completely. This cooling step is crucial—a warm cake will melt the buttercream and make layering difficult.
4. Create a double boiler by placing a heatproof bowl over a pot of gently simmering water (the bowl shouldn't touch the water). Add the egg whites and 1 cup sugar to the bowl, whisking constantly for 5-10 minutes until the mixture reaches 160°F on an instant-read thermometer and feels completely smooth with no grittiness—this pasteurizes the eggs and dissolves the sugar. Transfer to an electric mixer and beat on high speed for 7-10 minutes until thick, glossy, and cooled to room temperature. The mixture should hold stiff peaks.
5. With the mixer on medium-low speed, add the softened butter 2 tablespoons at a time, allowing each addition to incorporate fully before adding the next (this may take 5-7 minutes total). Once all butter is incorporated, add the vanilla and beat briefly to combine. Gently fold in the cooled rhubarb-raspberry compote from Step 1 and the strained raspberry jam, using a spatula to fold just until marbled throughout—don't overmix or you'll lose the pretty swirl. I like to leave some jam visible rather than fully incorporate it, which keeps pockets of intense fruit flavor and a beautiful presentation.
6. Place the first cooled cake layer on a cake board or serving plate and spread a thin layer of the fruit-swirled buttercream from Step 5 on top. Add another thin layer of buttercream, then add the second cake layer and press gently. Chill the assembled cake for 30 minutes in the refrigerator—this firms up the filling and makes frosting the exterior cleaner and easier. Remove from the fridge and frost the top and sides with the remaining buttercream, using an offset spatula for a smooth finish or creating decorative swirls as desired. Chill for at least 30 minutes before serving so the frosting sets properly.