Preheat your oven to 350°F (175°C).

Combine the flour and powdered sugar in a mixing bowl. Add the cold, cubed butter, then mix until the mixture resembles coarse crumbs.

Incorporate the egg yolk into the mixture. Mix until combined, and if the dough feels too dry, add cold water, one tablespoon at a time.

Press the dough into a 9-inch tart pan, spreading it evenly and pricking the bottom with a fork.

Bake for 15–20 minutes until lightly golden. Let it cool completely.

Heat the heavy cream in a saucepan over medium heat until simmering. Remove from heat.

Add the chopped white chocolate to the hot cream, then stir until smooth. Stir in the butter and vanilla extract.

Cool the mixture for about 10 minutes before pouring it into the cooled tart crust.

Refrigerate the tart for at least 1 hour or until the filling is fully set.

Arrange the mixed fresh berries on top.

Garnish with mint leaves and optionally dust with powdered sugar before serving.

Slice the tart and serve chilled.