Make the Tart Crust: In a mixing bowl, combine the flour and powdered sugar. Add the chilled cubed butter and use a pastry cutter or your fingers to blend until the mixture resembles coarse crumbs.

Incorporate Egg Yolk: Add the egg yolk and cold water to the flour mixture. Mix until a dough forms. Wrap the dough in plastic wrap and refrigerate for 30 minutes.

Prepare Tart Shells: Preheat the oven to 350°F (175°C). On a lightly floured surface, roll out the chilled dough to about ⅛-inch thickness. Cut into circles and place them into greased tart pans. Prick the bottom with a fork.

Bake Tarts: Bake the crusts in preheated oven for 15-20 minutes or until golden brown. Allow to cool completely on a wire rack.

Make Vanilla Cream Filling: In a saucepan, combine the heavy cream, milk, granulated sugar, and cornstarch. Heat over medium heat, stirring constantly until it thickens and bubbles, approximately 5-7 minutes. Remove from heat and stir in vanilla extract. Let it cool slightly.

Assemble Tarts: Once the tart shells are cooled and the cream is thick but still pourable, fill each tart shell generously with the vanilla cream.

Add Fresh Raspberries: Top each tart with fresh raspberries, arranging them artfully on the cream.

Refrigerate: Chill the assembled tarts in the refrigerator for at least one hour to set the filling.

Serve: To serve, garnish with mint leaves if desired and enjoy this delightful dessert!