Pour the milk into a saucepan, add the white sliced leeks, bay leaves and salt and pepper, then bring to the boil. Set aside for 10 minutes. Grill the gammon steak on a foil-lined grill pan for 7–8 minutes, turning once, until cooked. Trim off the fat, then dice the meat.
Heat the butter in a saucepan, stir in the flour, cook for 1–2 minutes, then gradually mix in the strained milk. Bring to the boil, stirring until smooth. Discard the bay leaves, then return the white leeks to the sauce, add the green sliced leeks and cook gently for 2–3 minutes, stirring until the leeks are just cooked. Leave to cool.
Make the pastry according to the method on
Reserve one-third of the pastry, roll out the remainder thinly, then cut 6 × 15 cm (6 inch) circles. Press into buttered individual tart tins, 10 cm (4 inches) in diameter and 2.5 cm (1 inch) deep. Trim off the excess pastry and reknead and reroll the trimmings as needed.
Stir the cockles and gammon into the sauce, then spoon into the pastry bases. Brush the edges with egg. Roll out the reserved pastry and cut 12 cm (5 inch) circles for the lids. Press the pastry edges together and flute (see
Bake the pies on a baking sheet in a preheated oven, 190°C (375°F), Gas Mark 5, for 30–35 minutes until golden brown. Serve with steamed baby carrots.