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rhubarb lunar cake

Simple Rhubarb Lunar Cake

Delicious Simple Rhubarb Lunar Cake recipe with step-by-step instructions.
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Prep Time 20 minutes
Cook Time 35 minutes
Total Time 55 minutes
Servings: 8 slices
Calories: 1175
Ingredients Method

Ingredients
  

For the cake
  • 3/4 cup sugar
  • 1/3 cup brown sugar
  • 1/3 cup butter (I prefer Kerrygold unsalted for this)
  • 1 large egg
  • 1 tsp vanilla
  • 1 1/4 cups flour (I always use King Arthur all-purpose)
  • 1/2 cup buttermilk (room temperature, about 70°F)
  • 1/2 tsp baking soda
  • 1/2 tsp baking powder
  • 1 tsp cinnamon
  • 1/4 tsp salt
  • 1 1/2 cups rhubarb (cut into 1/2-inch slices)
  • 2 oz cream cheese, softened
For the topping
  • 1/2 tsp cinnamon
  • 1/3 cup brown sugar
  • 1/3 cup walnuts (coarsely chopped, about 1/4-inch pieces)

Method
 

  1. Start by preheating your oven to 350°F. While it heats, cut the rhubarb into 1/2-inch slices and set aside. Chop the walnuts into coarse 1/4-inch pieces. Measure out all your dry ingredients and wet ingredients so everything is ready to go—this prevents overmixing the batter later. Let your buttermilk sit at room temperature if it isn't already, as this helps the batter mix more smoothly.
  2. In a small bowl, combine the softened cream cheese, 1/3 cup brown sugar, and 1/2 tsp cinnamon, stirring until well blended. Fold in the chopped walnuts gently so they're evenly distributed throughout the mixture. Set this aside—I like to make the topping first so it's ready to go the moment the batter is poured into the pan, ensuring the topping doesn't sink.
  3. Whisk together the flour, baking soda, baking powder, 1 tsp cinnamon, and salt in a medium bowl. Make sure these are evenly distributed with no lumps, as this creates a consistent crumb structure in the finished cake.
  4. In a large bowl, beat together the 3/4 cup sugar, 1/3 cup brown sugar, and butter until light and fluffy, about 2-3 minutes. This incorporates air into the batter, which helps the cake rise evenly. Add the egg and vanilla extract, beating well until the mixture is pale and smooth, another 1-2 minutes.
  5. Alternate adding the dry ingredient mixture from Step 3 and the room-temperature buttermilk to the creamed mixture from Step 4, starting and ending with the dry ingredients—this prevents the batter from becoming tough. Stir until just smooth, being careful not to overmix. Gently fold in the rhubarb slices from Step 1, distributing them evenly throughout without crushing them.
  6. Pour the rhubarb batter into a greased 8x8-inch or 9x13-inch baking dish. Spread the topping mixture from Step 2 evenly over the batter, making sure it's distributed to the edges. Bake for 30-40 minutes in an 8x8 pan or 45 minutes in a 9x13 pan, until a toothpick inserted in the center comes out clean or with just a few moist crumbs.
  7. Remove the cake from the oven and let it cool in the pan for 10-15 minutes before serving. This allows the structure to set while the cake is still warm enough to enjoy with the rhubarb and cream cheese topping at their best textures. I like to serve this cake slightly warm for the most tender crumb and melted topping.