Breton Shortbread: Mix the butter, sugar, and salt together by hand or with a mixer. Add the egg yolks and mix well. Sift the flour and baking powder over the butter and egg mixture, then mix until combined. Cover the dough with plastic wrap, pressing it directly onto the surface, and refrigerate for at least 2 hours, up to 12 hours.

Remove from the fridge and roll out the dough to a 1/4-inch (6 mm) thickness. Cut out a circle or square using a pastry ring, removing any excess dough (you can use the scraps to make cookies). Bake in a preheated oven at 320°F (160°C) for about 30 to 40 minutes, depending on your oven. When done, remove from the oven and let the shortbread cool on a wire rack.

Raspberry Mousse: Press the raspberries through a food mill to make a seedless puree, then stir in 2 sheets of gelatin that have been softened and melted in 2 tablespoons hot water.

Whip the cream with the powdered sugar until stiff peaks form, then gently fold it into the cooled raspberry mixture. Spread this over the Breton shortbread, making sure the pastry ring is in place around the base. Chill in the refrigerator for 15 minutes to set.

Lemon Mousse: Heat 1/2 cup (120 ml) of lemon juice and add the gelatin sheets that have been softened in cold water. Stir this mixture into the remaining lemon juice along with the zest. Let cool. Whip the cream with the powdered sugar until stiff peaks form, then gently fold it into the lemon mixture. Spread this over the raspberry mousse and refrigerate until the next day.

The next day, remove the ring and decorate as desired. For this version, 1 sheet of gelatin was melted in lemon juice with added sugar, then topped with fresh fruit and mint leaves.