Heat your oven to 180°C (350°F). Line a 9x13 inch baking dish with parchment paper, allowing some overhang for easy removal. While the oven preheats, measure out all your dry ingredients for the brownie layer (cocoa powder, flour, espresso powder, baking powder) and set aside. Chop the dark chocolate into roughly 1/2-inch pieces and measure out your aquafaba, sugar, butter, and oils. Having everything prepared before you start ensures smooth workflow between the brownie and ladyfinger layers.

In a small bowl, whisk together the cocoa powder, 6 oz flour, espresso powder, and baking powder. In a separate heatproof bowl, melt the chopped chocolate and butter together over a pot of gently simmering water (double boiler method), stirring occasionally until completely smooth. In a large bowl, whip the 4 fl oz aquafaba with 9.85 oz sugar for about 5 minutes until the mixture becomes thick and pale—this creates lift without eggs. Gently fold the melted chocolate mixture into the whipped aquafaba, then carefully fold in the dry ingredient mixture until just combined. Pour the batter into your prepared baking dish and bake for 30-35 minutes until a toothpick inserted in the center comes out with a few moist crumbs. I like to underbake tiramisu brownies slightly so they stay fudgy; overbaking will make them too cake-like for this dessert.

While the brownie bakes, begin preparing the ladyfinger layer. In a clean bowl, whisk together the remaining 3 fl oz aquafaba with 1 tsp cream of tartar for 5-8 minutes until soft peaks form. Gradually add 3 oz sugar and continue whipping for another 5-8 minutes until stiff peaks form and the mixture is glossy. In a separate bowl, whisk together 1 fl oz sunflower oil, 2 tsp yogurt, 1.5 oz chilled coconut cream (use just the solid part if it has separated), 1 tsp vanilla essence, and 1 tsp baking powder with 30g sugar until well combined. Gently fold the whipped aquafaba mixture into the yogurt mixture, then carefully fold in 5.3 oz flour. This batter needs to be pipeable but not too thin, so I prefer using a piping bag with a round tip to create uniform ladyfinger shapes.

Once the brownie layer is done, remove it from the oven and let it cool slightly while keeping the oven at 180°C. On a separate baking tray lined with parchment paper, pipe 4-inch lines of the ladyfinger batter, spacing them about an inch apart. Bake these for approximately 15 minutes until they're golden and springy to the touch. Remove the ladyfingers from the oven and let them cool completely on a wire rack while the brownie cools further.

While everything cools, brew your strong coffee by mixing 1 tsp espresso powder (or instant coffee) with 1 cup hot water, then let it cool for 5 minutes. Using an immersion blender or food processor, blend together the 12.35 oz silken tofu (which acts as the vegan substitute for mascarpone), 6 oz softened unsalted butter, 4.2 oz yogurt, 4.2 oz sugar, and 1.5 tsp vanilla bean paste until completely smooth and creamy. Once the cooled brownies and ladyfingers are ready, arrange the ladyfingers on top of the brownie layer. Quickly dip each ladyfinger into the cooled coffee (just a quick dunk on both sides—don't oversoak) and place it back on the brownie. Spread the silken tofu-based mascarpone cream evenly over the ladyfinger layer using an offset spatula or the back of a spoon.

Cover the assembled tiramisu brownies with plastic wrap and refrigerate for at least 8 hours, or ideally overnight, so the flavors meld and the texture sets properly. When ready to serve, dust the top generously with cocoa powder using a fine-mesh sieve. Use a sharp knife dipped in hot water and wiped clean between cuts to slice into squares. I find that chilling overnight actually improves these brownies—the coffee flavor deepens and the layers become more distinct.