Preheat oven to 375°F.

In a bowl, combine flour, sugar, and salt. Cut in butter until the mixture resembles coarse crumbs. Add egg yolk and cold water, mixing just until a dough forms. Shape into a disk.

Roll out dough and press into a 9-inch tart pan. Trim edges and prick the bottom lightly with a fork. Chill in the fridge for 10–15 minutes to help prevent shrinking.

In a bowl, gently toss peaches and blueberries with sugar, cornstarch, lemon zest, lemon juice, vanilla, and salt.

Arrange fruit evenly in the tart shell, spreading into an even layer.

Bake for 45–50 minutes, until crust is golden and the filling is bubbling and set. If edges brown too quickly, loosely cover with foil.

Let cool before slicing for clean pieces. Serve at room temperature. Enjoy!