A speciality of the Picardie region in France, flamiche is made as an open tart and a closed pie. It is usually made with leeks but sometimes with onion or pumpkin.
To make the tart pastry, sift the flour and a pinch of salt into a large bowl. Add the butter and rub in with your fingertips until the mixture resembles breadcrumbs. Add the egg yolk, 2–3teaspoons of chilled water and mix with a flat-bladed knife until the d