Chop butter into small cubes and then place with flour and lemon zest in a food processor.

Blend until it resembles large breadcrumbs. Add sour cream gradually. Check the consistency before adding all of the sour cream and do not add it all if it is not needed.Turn pastry onto a floured surface and pull together with your hands into a rectangle. Be careful not to over-mix or pastry will become too elastic and doughy.

Cover with plastic wrap and refrigerate for 30 minutes or, even better, overnight.

Gently re-work pastry before using, taking care to ensure it remains cold and firm.

Reproduced with permission from Pie by Dean Brettschneider. Published by Penguin Group NZ. RRP $54.99. Copyright © Dean Brettschneider, 2012. Copyright photography © Aaron McLean, 2012