Use a whole 250g packet of butter and a whole 250g packet of white cooking fat. Divide the pastry dough into three, and freeze two pieces for later use. Freezing the pastry before it's cooked does it no harm, just allow it to defrost slowly.

Beat together the egg yolks, egg, lemon juice and water and chill in the refrigerator - this will thicken the liquid slightly.

Cut the fats into small dice. Sieve flour and icing sugar together into a large mixing bowl.

Rub the fats into the flour mixture to make a fine crumb - use only your fingertips. Add all the liquid at once. Stir until the mixture starts to bind, then finish with your hand.

Knead gently on a lightly floured surface. Cover the pastry in plastic wrap and leave to rest for about an hour in the fridge. Roll out as required.