Step 1 Combine the flour, salt and lemon zest in a bowl. Add the butter and blend in using a pastry blender or 2 knives, working the ingredients to a coarse meal. Add the egg yolks, kneading in the bowl until the dough holds together and becomes smooth. (The dough can also be made in a food processor.) Cut the pastry in half, wrap both halves in plastic; refrigerate 1 hour.