Preheat your oven to 350°F (175°C). In a mixing bowl, combine the all-purpose flour, kosher salt, and powdered sugar. Whisk until evenly mixed.
Add the cold, cut pieces of unsalted butter. Blend until the mixture resembles coarse crumbs. Stir in the vanilla extract.
If the mixture is too crumbly, add cold water a teaspoon at a time until it forms a cohesive dough. Divide the dough among mini tart pans, pressing it evenly across the bottom and up the sides.
Bake for 15-18 minutes or until the crusts are lightly golden. Remove from the oven and cool completely in the pans.
In a clean mixing bowl, combine the heavy whipping cream, mascarpone cheese, softened cream cheese, and powdered sugar. Beat until fluffy and smooth.
Once the tart shells are cool, remove them from the pans. Spoon the cream filling into each tart shell, leaving some room for the fruits.
Arrange assorted fresh fruits on top of the cream filling. Chill for at least an hour before serving.
