Step 1: To make the pastry, dice the butter, then pulse with the flour in a food processor until the mixture resembles fine breadcrumbs.

Step 2: Add the sour cream and continue to pulse until the dough starts to incorporate into a ball.

Step 3: Wrap the dough in plastic film and refrigerate for 20 minutes.

Step 4: 
Roll the chilled pastry out until 3 mm thick and cut to suit your chosen recipe.