Heat the oven to 350°.
For the crust, whisk together the flour, baking powder and salt and set aside.
Mix the butter, sugar and egg until fluffy. Stir in the whiskey and vanilla and then beat in the dry mixture.
Add water by the tablespoon to bring the crust together, if needed.
Dump the dough out onto a well-floured work surface and knead to blend well.
Divide and shape the dough into 2 discs, one a little larger than the other.
Roll the larger one between 2 sheets of wax paper to 1/8-inch thickness for the bottom crust. Place in a pie pan and trim the overhang. Roll out the top crust in the same way to have it ready when you make the filling.
For the filling, beat the eggs until foamy.
Gradually add the sugar.
Add the ricotta and whiskey and stir to combine well. Pour into the prepared crust.
Crimp the edges of the top crust to the bottom crust.
Brush the top crust with a beaten egg yolk and score with a sharp knife to allow movement and venting as the filling expands.
Bake for 1 hour.
The filling will still jiggle when pulled out of the oven but will firm up from residual heat as it cools.
Allow the pie to cool completely before cutting. Sprinkle generously with powdered sugar to serve.
Store refrigerated for up to 5 days.