Preheat oven to 350°F (175°C). Grease and line a 9-inch springform pan with parchment paper.

Beat eggs and 1 cup sugar on high speed for 8-10 minutes until pale, thick, and tripled in volume.

Fold in flour, cornstarch, baking powder, and salt in three additions. Add vanilla extract. Pour into pan.

Bake for 25-30 minutes until golden and springy. Cool completely in pan, then remove.

Heat milk with vanilla bean paste until just simmering. Whisk egg yolks with 1/3 cup sugar until pale, then add 3 tablespoons cornstarch.

Temper yolks with hot milk, return to saucepan, and cook over medium heat, stirring constantly, until thick and bubbling.

Remove from heat and whisk in butter. Press plastic wrap onto surface and refrigerate until cold, at least 3 hours.

Slice cooled cake horizontally into three even layers using a serrated knife.

Place bottom layer on serving plate and spread with raspberry jam, leaving 1/2-inch border.

Top with second cake layer, then spread half the cold custard over it.

Add third layer and remaining custard, creating a slight dome shape.

Whip heavy cream with powdered sugar until stiff peaks form. Spread over entire cake, smoothing into rounded dome.

Roll out green marzipan into circle large enough to drape over cake. Place over whipped cream and press gently.

Trim excess marzipan at base. Dust with powdered sugar and top with pink marzipan rose.

Refrigerate for at least 2 hours before serving. Cut with sharp knife for neat slices.