Melt the dark chocolate in a heatproof bowl over simmering water. Let cool slightly.

Whip the heavy cream until soft peaks form. Fold in the melted chocolate.

In another bowl, beat the egg whites until soft peaks form. Gradually add sugar and beat until stiff peaks form.

Gently fold the egg whites into the chocolate mixture. Spoon into cups and refrigerate until set.

Preheat the oven to 350°F (175°C). In a bowl, mix flour, butter, and powdered sugar until crumbly.

Add the egg yolk and mix until a dough forms. Press into muffin tin and bake for 10-12 minutes.

Let cool, then fill each tart shell with pastry cream and top with mixed berries.

Preheat the oven to 325°F (160°C). Mix graham cracker crumbs and melted butter, then press into the bottom of muffin tins.

In a bowl, beat cream cheese, sugar, vanilla, and egg until smooth. Pour over the crusts.

Bake for 15-20 minutes until set. Let cool and refrigerate before serving.