Fraisier — strawberry cake with vanilla mousseline cream

Line the base of a 20 cm springform pan with parchment paper; do not grease the sides. Preheat the oven to 170°C with conventional top and bottom heat. Beat the three whole eggs and 90 g sugar with an electric mixer for about 8–10 minutes, until very pale and thick and several times their original volume. Sift in the 90 g flour and gently fold it in with a spatula in two additions, reaching the bottom of the bowl. Transfer to the pan, level the surface and bake for about 25–30 minutes, until the top springs back and a skewer inserted in the center comes out without wet batter. Leave for 10 minutes, loosen the sides with a thin knife, remove the sponge and peel off the paper. Cool on a rack for about 45–60 minutes.

Split the vanilla bean and scrape out the seeds. Pour the weighed 400 g milk into a small saucepan, add the seeds, empty pod and 45 g sugar from the cream allocation. Heat until it steams clearly and small bubbles appear around the edge, then remove the empty pod. In a bowl, mix the four additional yolks, the remaining 45 g sugar for the cream and all the cornstarch. Gradually pour in about half the hot milk, whisking constantly, then return the mixture to the saucepan with the remaining milk. Do not add the reserved egg whites.

Heat the mixture over medium-low heat, whisking vigorously all the time across the bottom and around the sides. Once it thickens and starts bubbling clearly, cook for a full 2 more minutes without stopping stirring. Take off the heat, add the 90 g butter intended for the hot custard base and mix until fully incorporated. The custard should be smooth and thick, without lumps of starch.

Transfer the custard to a wide, shallow dish in a layer about 2 cm deep. Stand the dish in cold water for about 10–15 minutes, stirring the custard a few times and making sure no water gets inside. Then cover the surface with plastic wrap in direct contact and refrigerate for about 45–60 minutes, until cool. Meanwhile, heat the 60 g water and 30 g sugar for the syrup just until the sugar dissolves and the mixture briefly boils. Set aside to cool; do not reduce it for long. Measure out about 60 g cool syrup for the cake and reserve the rest for another use.

Cut the completely cooled sponge horizontally into two layers. Using a small plate or template, trim each to 18 cm in diameter; set the trimmed edges aside outside the cake servings. Briefly wash the strawberries before hulling, dry thoroughly and weigh out 600 g edible fruit. Reserve 150 g for decoration. From the remaining 450 g, choose berries of similar height for the border and halve them lengthwise; cut the rest into small pieces. Take the cool custard out for about 15–20 minutes during these preparations so it softens enough to stir smoothly; it should not be hot or rock hard from chilling.

The remaining 90 g butter should be soft and easy to press with a spatula, but it must not be liquid. Smooth out the custard with a whisk or briefly with a mixer; the custard and butter should have a similar cool softness. Beat the butter with an electric mixer for about 2 minutes, then add the custard a generous spoonful at a time, beating continuously and scraping down the sides. Finally, beat briefly until smooth and fluffy. If the cream becomes grainy because the ingredients are too cold, stop adding custard, briefly hold a warm towel against the outside of the bowl and beat again. Use the finished cream immediately to assemble the cake.

Place a cake ring 20 cm in diameter and 8 cm high on a flat plate, lined inside with an acetate strip intended for food. Center the first 18 cm sponge layer inside and soak it with half the measured syrup, about 30 g. Stand the strawberry halves side by side against the ring, cut sides facing outward, in the empty space around the sponge. Add cream between and behind the berries, carefully filling the gaps with a spatula or piping bag. Also spread a thin layer of cream over the sponge.

Reserve about one quarter of the cream for the top and finishing the sides. Spread the remaining cream inside, alternating with all the prepared strawberry pieces from the 450 g allocation, pressing gently so there are no empty spaces. Add the second sponge layer, press lightly and soak with the remaining approximately 30 g syrup. Spread the reserved cream into the gap around the sponge and thinly over the top, using it all. There is no need to fill the ring to the top. Cover the cake so the cover does not touch the cream and immediately refrigerate for at least 6 hours, preferably overnight. Refrigerate the strawberries reserved for decoration separately.

Carefully release the thoroughly chilled cake from the ring and remove the acetate. Arrange all 150 g reserved strawberries on top, cut into halves or quarters. Do not add unlisted toppings, glaze or marzipan. Take the cake out about 10–15 minutes before serving and cut into eight portions with a sharp knife, wiping the blade after each cut. Keep refrigerated until serving and between slicing portions; the cake is best eaten within 24 hours of assembly.