The sponge cake layers and the vanilla pastry cream need to cool completely before being used to assemble the cake. They can be prepared the night before. For the sponge cake, line two, 8-inch (20-cm) cake pans with parchment paper; do not grease the sides. Preheat the oven to 350F/177C. If you don’t want a super tall cake, prepare this cake recipe as a two-layer, 10-inch cake.
Place the eggs, sugar and vanilla into a mixer bowl and whisk on high speed for 7 to 9 minutes, until the eggs are thick, pale and voluminous. In a separate bowl, combine the dry ingredients: flour and baking powder. Once the eggs are ready, sift the dry ingredients into the eggs in small increments or one-third at a time. Using a spatula, fold the flour gently but thoroughly into the eggs, mixing from the bottom of the mixing bowl.
Divide the cake batter evenly between the prepared pans. Bake in the preheated oven for 20 to 22 minutes, or until the top of the cake turns a rich, golden-brown color. Immediately after removing the cake from the oven, run a knife along the edge of the pan to release the cake. This will allow it stay level as it cools. Allow the cake layers to cool completely on a wire rack.
Making the Vanilla Pastry Cream:
For the vanilla pastry cream: Place the milk into a medium-sized saucepan and whisk the flour in until no clumps remain. Cook the milk over medium-low heat for approximately 5 minutes, until the milk is steaming hot but not boiling. Meanwhile, in a separate bowl, whisk the eggs and sugar together for a few minutes until the mixture is thick and pale. If the mixture is too thick, add 1 teaspoon of water. In a small ramekin, combine the cornstarch and water, then add this slurry to the egg yolk mixture and whisk briefly.
Slowly temper the hot milk into the egg yolk mixture, whisking for about 30 seconds in between additions. Once the two mixtures have been combined together, pour it back into the saucepan. Cook the custard over medium heat, running a rubber spatula along the bottom the entire time to keep the custard from burning. Cook for 4 to 5 minutes, until a thick pudding forms. It should hold its shape on the back of a spoon. If any clumps form, give the custard a quick whisk. Remove the custard from the heat and add the butter and vanilla, then whisk until the butter is completely melted. Cover the custard with a lid or plastic wrap and cool completely in the refrigerator.
Making the Tiramisu Filling:
For the tiramisu filling: once the custard is cooled, prepare the filling. Place the softened cream cheese or mascarpone into a large mixing bowl and whisk for a few minutes until it’s smooth and creamy. Next, add in the confectioner’s sugar, raspberry liqueur and heavy cream. Whisk for 4 to 5 minutes until stiff peaks form. In a small ramekin, combine the gelatin and water and stir until well combined. Microwave the gelatin for about 30 seconds, until it’s dissolved. The mixture will be hot! Do not wait for the gelatin to cool!! Add the hot gelatin into the whipped cream and whisk for about 30 seconds.
Start adding the chilled custard, about 1 cup at a time, and fold gently but thoroughly after each addition, keeping the whipped cream fluffy.
Assembling the Cake:
To assemble the cake, line the sides of a springform pan with an acetate cake collar or foil. Split each sponge cake layer in half using a sharp serrated knife, creating 4 layers total. Drop the first sponge cake layer into the bottom of the pan and soak it lightly with raspberry liqueur. Next, add a few tablespoons of raspberry preserves and spread evenly to the edges. Add about 1 cup (240 ml) of the tiramisu filling, spreading it evenly to the edges. Next, add a layer of fresh raspberries, about 25 to 30 per layer. Add more cream over the raspberries to seal them in. Watch my video recipe to see how I put the cake together!
Top the raspberry layer with the next sponge cake and repeat the process. For the final layer, first soak the cake lightly with liqueur, then invert onto the top. Add the remaining cream on top and garnish with a layer of fresh raspberries.
Refrigerate the cake overnight to allow the filling to set. When ready to enjoy, unlock the springform pan and transfer the cake onto a stand. Watch my video recipe to see how I do it. Remove the plastic wrap and garnish the sides of the cake with ladyfinger cookies. If desired, wrap the cake with a ribbon for additional garnish.