In a mixing bowl, combine chilled unsalted butter, all-purpose flour, granulated sugar, one large egg, one egg yolk, vanilla extract, and a pinch of salt. Blend until a soft dough forms, about 5-7 minutes.

Wrap the pastry dough tightly in plastic wrap and refrigerate it for at least 30 minutes.

In a saucepan over medium heat, warm 2 cups of whole milk until just below boiling. In a separate bowl, whisk together three egg yolks, granulated sugar, cornstarch, and lemon zest.

Slowly pour the hot milk into the egg mixture, whisking constantly. Return the mixture to the saucepan and cook over medium heat until thickened, about 5-7 minutes.

Transfer the thickened custard to a bowl and cover the surface with plastic wrap pressed directly onto it to prevent a skin from forming.

Preheat your oven to 350°F (175°C), ensuring it reaches the desired temperature before baking.

Once the dough has chilled, dust your countertop with flour and roll it out to about ¼ inch thickness.

Grease a tart pan with butter or cooking spray, then carefully transfer the rolled-out dough into the pan.

Once the custard has cooled completely, pour it into the prepared pastry shell, ensuring even distribution.

Sprinkle a generous handful of pine nuts or sliced almonds over the custard filling.

Bake in the preheated oven for 30-35 minutes, or until the pastry is golden brown and the custard is set.

Allow the tart to cool in the pan for about 30 minutes before transferring it to a wire rack.

Before serving, lightly dust your Italian Torta della Nonna with powdered sugar.