ingredients
serves 8
PASTRY
3 cups All purpose flour, plus extra to dust
1 tsp English mustard powder
3/4 cup cold butter, cut into cubes
1/2 tsp salt
1/2 cup mature Cheddar cheese, grated
2 medium egg yolks, lightly beaten
FILLING
2 pound leeks, trimmed
2 medium red onions, peeled
juice of 1/2 lemon
5 thyme sprigs, leaves only
salt and pepper
4 tbsp olive oil
TO GLAZE
1 small egg, lightly beaten
method
1. To make the pastry, put the flour, mustard, butter and salt into a food processor. Pulse until the mixture forms crumbs, then add the cheese, egg yolks and 2 - 3 tbsp cold water. Process briefly until the mixture comes together. Form into a ball, wrap in Saran wrap and put in the freezer for 10 minutes.
2. Cut the leeks into 1/2 inch slices, then wash and drain. Put the leeks into a microwave-proof bowl. Add 3 tbsp water, cover with Saran wrap, pierce the top and microwave on high for 8 minutes. (Alternatively, cook the leeks with the water in a small covered pan over a low heat until softened.) Drain in a colander, then set aside.
3. Cut each onion into 8 wedges, put into the bowl and toss in the lemon juice. Cover, pierce as before and microwave on high for 5 minutes. (Alternatively, gently cook the onions with the lemon juice in a small covered pan until softened.)
4. Roll out the pastry on a lightly floured large sheet of baking parchment to a 15 inch round. Lift the paper and pastry on to a large baking sheet.
5. Put the onions and leeks in the centre of the pastry, leaving a 3 inch border all round. Sprinkle the thyme leaves over the vegetables, season with salt and pepper, and drizzle with the olive oil.
6. Lift the pastry edges up and fold them over the vegetables at the edge. Brush the pastry rim with beaten egg and bake at 200°C (180°C fan oven) for 50 minutes or until the pastry is golden and the vegetables are tender.
