First make the filling. Put the chicken into a large saucepan and just cover with water or stock. Add the onion, bouquet garni and peppercorns and bring to the boil, skimming off any scum which rises to the surface. Reduce the heat to low, cover the pan and simmer the chicken for 1 hour, or until it is cooked through and tender. Remove the chicken from the pan and set aside until it is

cool enough to handle. Discard the cooking liquid and flavourings.

Meanwhile, to make the pastry, sift the flour, salt and cloves into a large bowl. Make a well in the centre and pour over the oil and water. Gradually incorporate the flour into the liquid, beating until it comes away from the sides of the bowl. Turn the dough out on to a lightly floured surface and knead lightly until it is smooth and elastic. Cover with a damp cloth and set aside in the refrigerator for 30 minutes.

Cut the chicken into bite-sized pieces and discard any bones or skin.

Heat the oil in a large, deep frying-pan. Add the leek, garlic and pepper and fry until they are soft. Stir in the ham, tomatoes and chicken and cook for 5 minutes, stirring constantly. Remove the pan from the heat.

Preheat the oven to moderately hot 190°C (Gas Mark 5, 375°F).

Divide the dough in half. On the lightly floured surface, roll out each half to a 23 cm (9 in) circle. Carefully transfer one half to a well-greased baking sheet. Arrange the filling in the centre of the circle, leaving at least a a 2 1/2 cm (1 in) edge all the way round. Using a rolling pin, carefully arrange the second dough circle over the filling. Roll up the edges and crimp them to seal. Cut a deep slit in the centre of the top dough circle. Brush the top and sides of the dough with the egg white mixture and put the baking sheet into the oven. Bake for 30 to 40 minutes, or until the pie is golden brown.

Remove from the oven and transfer the pie to a warmed serving dish. Serve at once.