Tuna casserole

Preheat the oven to 180 ºC (350 ºF). Grease an ovenproof dish with margarine. Boil the rice until cooked, then drain. Melt the butter, slowly stir in the cake flour and blend to form a smooth paste. Heat until the cake flour is cooked, stirring continuously. Slowly add the milk and blend until smooth. Stir continuously until the sauce comes to the boil and thickens. Add the tuna and season to taste with salt and black pepper.
Heat a little oil in a pan and sauté the celery and onion until soft. Add to the white sauce mixture and blend. Arrange layers of rice and the white sauce mixture in the prepared dish, ending with a layer of the white sauce mixture. Arrange the tomato slices on top and season lightly with salt and pepper. Combine Cheddar cheese and breadcrumbs and sprinkle on top. Bake for about 30 minutes or until the cheese has melted and the dish is heated through. Serve with salad. Serves 6-8.