Genoise sponge + syrup:

1. Preheat the oven to 350°F (180°C). Line a flat baking tray with baking paper and grease the sides of a 7-inch (18 cm) pastry ring (or use and grease sides and bottom of a spring form with detachable edges).
2. In a large mixing bowl, beat the eggs and sugar using an electric hand mixer for 10 minutes, until fluffy and tripled in volume. Add the sifted flour, cornstarch, and stir until combined.
3. Pour into the prepared form and spread with an offset spatula. Bake for 20 minutes. Let cool for a few minutes and invert onto a cooling rack.
4. For the syrup, pour sugar and water in a small saucepan. Bring to a gentle boil, then turn the heat to low and let simmer until syrupy. Let cool completely.

Mousseline cream:

1. Pour the milk into a large saucepan, then scrape the vanilla seeds from the pod and add the pod. Heat the milk to a gentle simmer and remove from heat immediately. Remove the vanilla pod.
2. In a large mixing bowl, whisk the yolks and sugar until fluffy. Add cornstarch and whisk well. Slowly pour the warm milk, whisking constantly.
3. Transfer back to the pan and heat on medium heat, whisking constantly, until mixture thickens.
4. As soon as the cream thickens, remove from heat and transfer to a clean bowl, cover with plastic wrap touching the surface. Place in the fridge to cool down until it reaches the temperature of 85-95°F (30-35°C). Use a baking thermometer to check.
5. Meanwhile, place softened butter in the bowl of a stand mixer fitted with the whisk and beat until whipped. Add the pastry cream in 3 additions, and whisk until light and fluffy, like a mousse texture. Transfer to a large piping bag with a round piping tip.

For assembling:

1. Slice in half all the strawberries you will need to place around the genoise sponge. Keep the other ones whole, but remove the stems.
2. Cut the genoise sponge in half lengthwise, using a serrated knife. Brush the top of each half with syrup, using a small pastry brush.
3. Place an 8-inch (20 cm) pastry ring onto a serving plate or cake stand, and line the inside of the ring with an acetate strip (also called ‘cake collar’).
4. Add the first genoise sponge in the center of the ring, then place the sliced strawberries around the edges, between the cake and the pastry ring, sliced-side facing out. Try to place them as tightly against each other as possible.
5. Pipe about half of the mousseline cream onto the genoise, and in between each strawberry. Add the remaining whole strawberries in the center, face down, covering the top with more cream as needed.
6. Place the second genoise sponge over, and gently press with the flat of your hand to avoid any large air pockets underneath. Pipe the remaining mousseline cream on top, and flatten out using an offset spatula. Place in the refrigerator for 4 to 6 hours, then carefully remove the pastry ring and acetate strip. Decorate with some strawberries and fresh mint leaves.* Allow to come to room temperature for about 20 minutes before serving. Enjoy with a glass of dessert wine or bubble wine.