Combine flour, sugar (if using), and salt in the canister of a food processor and pulse briefly to combine.

Scatter butter pieces over the top of the flour mixture and pulse again until butter is mostly combined and mixture resembles coarse crumbs (there should still be discernible pieces of butter remaining in the mixture, some as large as a chocolate chip).

Add sour cream and pulse again until mixture just begins to cling together. The mixture may still seem dry, but if you pinch it between your thumb and forefinger and it clings together, you’re ready to move on — don't overdo it!

Transfer dough to a clean surface and work into a ball (try not to over-handle the dough, you want it to stay as cold as possible to keep the butter from melting and your hands are very warm!). Flatten into a disk, wrap tightly in plastic wrap, and transfer to refrigerator to chill for at least 45-60 minutes before proceeding/using as desired.

If arranging into a pie plate, remove the dough from the refrigerator once it has chilled and transfer to a clean, lightly floured surface. Use a rolling pin to roll into a 12” circle (add flour as needed and be sure to lift the pie dough and add flour beneath it while rolling to keep from sticking, if needed) and arrange into a pie plate, crimping or fluting the edges (I provide a visual on fluting the edges in my video above).

Transfer to pie plate and use according to your pie filling recipe’s instructions, or see my detailed tutorial on how to blind bake pie crust.