Prepare the Crust:
In a mixing bowl, combine the flour, cold butter, sugar, and salt. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs. Add the egg yolk and vanilla extract, and mix until the dough comes together. Form the dough into a disc, wrap it in plastic wrap, and refrigerate for at least 30 minutes.

Preheat Your Oven:
Preheat your oven to 375°F (190°C). Grease a 9-inch pie dish or tart pan.

Roll Out the Dough:
On a lightly floured surface, roll out the chilled dough into a circle slightly larger than your pie dish. Carefully transfer the dough to the dish, pressing it gently into the bottom and sides. Trim any excess dough and crimp the edges decoratively. Prick the bottom of the crust with a fork to prevent puffing during baking.

Blind Bake the Crust:
Line the crust with parchment paper or aluminum foil and fill it with pie weights or dried beans. Bake for 10–12 minutes, then remove the weights and bake for an additional 5 minutes, or until the crust is lightly golden. Set aside to cool slightly.

Make the Filling:
In a large mixing bowl, whisk together the ricotta cheese, sugar, eggs, vanilla extract, lemon zest, and cinnamon (if using). Mix until smooth and creamy. If adding optional ingredients like chocolate chips or candied fruit, fold them in gently at this stage.

Assemble and Bake:
Pour the ricotta filling into the pre-baked crust, spreading it evenly. Bake in the preheated oven for 35–40 minutes, or until the filling is set and the top is lightly golden. To check for doneness, insert a knife into the center—it should come out clean.

Cool and Serve:
Let the pie cool completely on a wire rack before slicing. Dust with powdered sugar or garnish with fresh berries for an elegant finish. Serve at room temperature or chilled, depending on your preference.