Preheat the oven to 350℉, then place the cold dough on a workspace that's been lightly dusted with flour. Dust your rolling pin and the dough, then roll it out to fit a 9-inch deep dish pie plate (about 11 inches).
Transfer the dough to the pie plate and tuck any loose edges under, then press gently to fit. Place the crust in the freezer while you make the filling.
Use an electric mixer to whip the ricotta, sour cream and sugar for 2-3 minutes until light and fluffy (it will still be quite grainy).
Beat in the flour, vanilla, lemon zest, lemon juice, and salt. Then add the eggs one at a time, being sure each one is fully incorporated before adding the next.
Remove the pie crust from the freezer, then pour in the filling and smooth out the top.
Dust the top all over with cinnamon, then bake for about 50 minutes or until the crust is golden brown and the center is mostly set with just a little bit of jiggle in the center.
Remove from the oven and let cool, then transfer to the refrigerator to chill completely for about 5-6 hours or overnight.
Slice into wedges and serve with extra whipped cream on top!
