In a food processor, combine 2 1/2 cups flour, 1/2 cup sugar, and 1/4 teaspoon salt. Pulse to mix.

Add cold butter cubes and pulse until the mixture resembles coarse crumbs.

Beat 1 egg with 2 tablespoons ice water and add to the flour mixture. Pulse until dough forms.

Turn dough onto a floured surface, knead gently, shape into a disc, wrap, and refrigerate for 30 minutes.

Preheat oven to 350°F (175°C).

Roll out dough to fit a 9-inch pie dish. Press into dish, trim excess, and crimp edges.

In a bowl, mix ricotta, 1 cup sugar, 4 eggs, vanilla, lemon zest, and 1/4 cup flour until smooth.

Pour filling into crust and smooth the top.

Bake for 50-60 minutes or until filling is set and crust is golden.

Cool on a wire rack, then refrigerate for a few hours.

Dust with powdered sugar before serving.