Preheat oven to 425°F (220°C). Drain any excess liquid from cherries, nectarines, and apricots.

In a medium bowl, combine flour and salt. Cut 3/4 cup of butter into the flour mixture until it resembles coarse crumbs. Gradually add water until dough sticks together. Divide dough into two parts, roll one half into a circle 1/8 inch thick and place in a 9-inch pie pan. Roll out the remaining dough and cut into long strips for lattice topping.

For the filling, mix drained fruit with sugar, cinnamon, cornstarch, and flour. Pour into the prepared pie pan and dot with 2 tablespoons of butter.

Arrange pastry strips into a lattice top and crimp edges. Whisk egg yolk and water, brush it on lattice strips.