For the Tart Crust:
Mix flour, salt and powdered sugar.
Add butter pieces and work into the flour, creating thin sheets of butter in the flour.
Mix egg yolk with 1 tablespoon water in a bowl then add it to the flour and butter mix.
Continue to work with your fingers until the mixture sticks together when pinched.
Add another tablespoon of water if needed.
Press dough into a buttered tart pan with a removable bottom (or use a 10" round pan).
Prick the crust with a fork and then refrigerate for an hour.
Preheat the oven to 375, then bake for 12 to 15 minutes or until golden brown.
Allow to cool completely before filling with mascarpone filling.
For the Filling:
Whip cream on high with a mixer.
Add softened mascarpone cheese and powdered sugar, then beat to mix well.
Fold in the lemon curd with a wooden spoon.
In a separate bowl, mix raspberries and sliced strawberries.
Heat strawberry preserves until thinned, then mix into the berries.
Spoon the mascarpone into a cooled tart crust and top with berries.
Garnish with mint leaves if desired. Enjoy!