Combine the flour, sugar, baking powder, and salt in a large mixing bowl. Add the cold butter cubes and rub in with your fingertips until the mixture resembles coarse breadcrumbs.

Add the beaten eggs and mix until the dough just comes together. Do not overwork it.

Divide the dough into two portions: two-thirds for the base and one-third for the crumb. Wrap both in plastic wrap. Refrigerate the larger portion for 30 minutes. Place the smaller portion in the freezer for 30 minutes.

While the dough chills, beat the drained ricotta and caster sugar together with an electric hand mixer until smooth, about 1 minute.

Add the egg, egg yolk, lemon zest, and vanilla extract. Mix on low speed until just combined and creamy. Set aside.

Heat the oven to 175 C / 350 F. Lightly butter a 9-inch tart pan with a removable base.

Remove the larger dough portion from the fridge. Press it evenly across the base and up the sides of the pan to about 2 cm height. Keep the thickness even throughout.

Pour the ricotta filling over the base and smooth it level with a spatula.

Remove the frozen dough portion from the freezer. Grate it coarsely on a box grater directly over the filling, covering it in an even layer of crumbs.

Bake on the lower-middle oven rack for 40 to 45 minutes, until the crumb topping is deep golden and the filling is set with only a slight wobble at the very center.

Remove from the oven and cool completely in the pan on a wire rack, at least 1 hour, before removing and slicing.

Dust with powdered sugar just before serving.