Combine the flour and powdered sugar in a mixing bowl.
Add the cold, small pieces of butter and cut in with a pastry cutter or pulse in a food processor until the mixture resembles coarse crumbs.
Mix in the egg yolk until the dough begins to come together, then knead gently just to form a cohesive ball.
Wrap the dough in plastic and chill in the fridge for about 20 minutes to relax the gluten.
Preheat the oven to 350°F (175°C). Roll out the chilled dough on a lightly floured surface to about 1/8 inch thick.
Cut out small circles and press them into tartlet pans or muffin tins, trimming off excess dough.
Prick the bottoms of the shells with a fork and blind bake for 15 minutes or until golden brown.
While the crust bakes, whisk together the mascarpone, sugar, lemon zest, and lemon juice until smooth and slightly thickened.
Once the crusts are baked and cooled slightly, spread a layer of lemon curd into the base of each tartlet.
Spoon the mascarpone mixture on top of the lemon curd, smoothing the surface with a spatula.
Top each tart with halved strawberries for a vibrant, fresh burst of flavor and color.
Chill the assembled tartlets for at least 30 minutes before serving to allow flavors to meld and to set the mascarpone.
