Step 1

Preheat the oven to 200C/180 Fan/Gas

Step 2

To make the pastry, measure the flour and butter into a food processor and blend until the mixture resembles breadcrumbs. Add the egg and water and blend again until it forms a smooth dough ball. Roll on a lightly floured work surface and use the pastry to line a 28cm/11in loose-bottomed, deep quiche tin. Form a little lip around the top and prick the base with a fork. Place in the fridge for 15 minutes.

Step 3

Line with baking paper and baking beans and bake for 15 minutes. Remove the beans and paper and return to the oven for a further 5–10 minutes, or until just cooked and pale golden-brown. Reduce the oven temperature to 180C/160 Fan/Gas 4.

Step 4

To make the filling, heat the oil in a wide-based frying pan, add leeks and celery and fry over a high heat for few minutes.

Step 5

Lower the heat, cover and simmer for about 25 minutes, or until the vegetables are completely tender. Remove the lid, increase the heat and fry for a minute to cook off any excess water.

Step 6

Beat the eggs and cream together in a jug and season with salt and pepper.

Step 7

Spoon the soft leeks and celery into the pastry case, scatter with cheese and parsley and season with salt and pepper. Pour over the cream.

Step 8

Bake for about 35–40 minutes, or until golden-brown and just set on top. Leave to sit for about 5–10 minutes before turning out.