Mix the flour and sugar in a bowl until combined.
Add the cold diced butter to the flour mixture and cut it in with a pastry blender or your fingertips until the mixture resembles coarse crumbs.
Whisk the egg yolk and cold water together in a small bowl, then add it to the flour mixture.
Mix gently until the dough begins to come together, then knead lightly in the bowl to form a smooth, cohesive ball.
Wrap the dough in plastic wrap and chill in the refrigerator for about 30 minutes to relax.
Preheat your oven to 375°F (190°C). Roll out the chilled dough on a lightly floured surface to about 1/8-inch thickness.
Cut out rounds suitable for your tart pans and gently press them into the pans, trimming any excess dough.
Line the tart shells with parchment paper and fill with pie weights or dried beans. Bake for 15 minutes, then remove weights and parchment and bake for another 5 minutes until golden and crisp.
Meanwhile, prepare the strawberry filling by combining sliced strawberries, sugar, lemon juice, and cornstarch in a saucepan. Cook over medium heat, stirring gently, until the mixture thickens and the berries release their juices.
Remove the filling from heat and let it cool slightly until it thickens further to a jam-like consistency.
Fill each baked tart shell generously with the strawberry filling, ensuring the berries are evenly distributed.
Optional: Garnish with fresh sliced strawberries or a light glaze to give a shiny finish before serving.
