Cut butter into flour until it resembles crumbs. Stir in sour cream.

Turn onto a floured board and knead until it just holds together.

Form into a ball, flatten slightly and wrap airtight. Refrigerate at least 2 hours or overnight.

Work with half of the dough at a time and keep other half in the refrigerator until ready to use.

Pound the dough with a heavy rolling pin to make it pliable. Use in any recipe calling for puff pastry.