Place the milk in a medium saucepan. Stir in half the sugar. Heat over medium–high until the milk is almost boiliing.
Meanwhile whip the eggs with the rest of the sugar until lightened in colour. Whisk in the flour, cornstarch, and vanilla bean paste until smooth.
When the milk is hot, turn off the stove and pour the milk over the egg mixture and whisk well to properly incorporate all the ingredients.
Pour the mixture back into the saucepan and heat on medium heat until the mixture comes to a boil, whisking constantly.
Boil the mixture for 2 minutes until very thick, then immediately take off the heat and pour the custard over the strainer and push it through.
Cover the pastry cream with plastic wrap and let cool to room temperature.
Hot milk sponge cake
Preheat the oven to 350 °F. Butter and flour an 8-inch cake pan with 2-inch sides or an 8-inch springform. Line the bottom with parchment paper. Set aside.
In a small saucepan (or in a microwave safe bowl), heat the milk with the butter until the butter is melted on low heat. Add the vanilla and let cool slightly.
Sift the flour with the baking powder and salt into a medium bowl. Set aside.
In the bowl of an electric mixer fitted with the whisk attachment, whip the eggs with the sugar until very light and fluffy. The mixture should at least double in volume, if not more.
Add dry ingredients alternately with wet ingredients, beginning and ending with the dry.
Transfer the batter to the prepared cake pan and smooth it out. Tap the cake pan on the counter a few times to release any big air bubbles.
Bake the cake until golden brown. A cake tester inserted into the middle should come out clean. The cake will be spongy and light and spring back when gently pressed. This takes about 35 minutes.
Let cool slightly before unmoulding onto a wire rack to cool completely. You can cool the cake upside down to flatten the top.
In a small saucepan, combine the water and the sugar. Heat it on medium until the sugar is dissolved.
Remove from the heat and add the rum. Let cool.
In the bowl of a stand mixer fitted with the whisk attachment, whip the room temperature pastry cream to loosen it up.
Add the soft butter, a piece at a time, mixing well between each addition.
Add the vanilla extract. Whip the mixture until it is light and fluffy.
Transfer the mousseline to a large pastry bag and use immediately.
Prepare an 8-inch cake ring (from Amazon) by placing it on a parchment-lined rimmed (or your cake stand) baking sheet, lining the inside of the ring with a 26 inch long piece of acetate (also on Amazon).
Using a serrated knife, trim the top of the sponge cake if necessary so that it is flat and levelled.
Slice the sponge cake into two equal layers.
Place the bottom layer on the bottom of the ring and press it gently so that it fits flat.
Brush the cake with one third of the syrup, roughly 50 mL (a little more than 3 tbsp).
Slice 13 to 14 raspberries in half and arrange them neatly on top of the bottom layer of cake, pressing them gently against the acetate to set them in place.
Pipe half the mousseline in the middle and smooth it from edge to edge, gently pushing it against the berries to lock them in place.
Scatter raspberries over the mousseline (you'll need 50 to 60 berries depending on their size). Press the berries into the cream, gently.
Pipe the rest of the mousseline over the berries, then smooth it from edge to edge with an offset spatula. The berries should be completely covered.
Brush the underside of the top cake layer with 50 mL of syrup, then place over the mousseline cream, pressing gently to make sure there are no gaps of air.
Brush the top of the cake with the rest of the syrup.
Place the marzipan on top and press it gently to smooth it out.
Chill the cake in the fridge for at least 4 hours.
Before serving, remove the cake ring and gently peel off the acetate.
Let the cake sit at room temperature for 30 minutes so that the mousseline isn't too cold.
- If you have the patience, you can beat the eggs and sugar to the ribbon stage. If you don’t have the time, just make sure that they are frothy. I’m not sure that beating them to the ribbon stage is necessary, but this time I did go the extra mile and was pleased with the extra sponginess that it gave the final cake. - When adding the wet and the dry alternately, remember to start and end with the dry. Thus: dry, wet, dry, wet, dry. This is one of the golden rules of baking, although I’m not quite sure why. - We always butter (or spray with cooking spray) the inside of the pan and coat it with sugar (not flour) because sugar is delicious. Flour works best to prevent sticking. - The 35-minute baking time is pretty exact. Normally, my mom and her mom would bake this in a tube pan (angel food cake pan). It always takes exactly 35 minutes for the cake to bake. No joke. This time, I chose to deviate from the tradition, and I baked it in a loaf pan. And, once again, it came out perfectly! The only difference was that it baked for 47 minutes. Now, I’ve only baked it once in the loaf pan, so I cannot say for sure that it will take you 47 minutes. So start checking it after 45 minutes, or when you notice the edges coming away from the sides.