Ingredients:
* 250g (8 oz) shortcrust pastry
Filling:
* 50g (2 oz) Stork margarine
* 50g (2 oz) flour
* 275ml (1/2 pint) milk
* Salt and freshly ground black pepper
* A pinch of dry mustard
* 1 x 120 g (4 oz) can salmon, drained and flaked
* 1 hard-boiled egg, peeled and sliced
* 1 tomato, skinned and sliced
* Beaten egg or milk, to glaze