Stir in the flour and ground almonds together in a large bowl, then add the butter and rub in your fingertips until the mixture looks like crumbs. Stir in the sugar.
Break in the egg and work into the mixture with your fingers, breaking it together to form a soft dough.
Tip the dough onto a lightly floured work surface and shape it into a ball. Flatten with your fingers to a disc and wrap in cling film. Chill for at least 3 hours before using.
Roll 1-2 mm thick. For blind baking, fit into pan and chill dough. Bake at 375 degrees F. 1mm tart shells take about 10 minutes to brown in metal pans.
