Heat butter or margarine in a saucepan. Add the minced meat in flakes and brown while stirring. Clean, wash and cut the vegetables into pieces. Braise everything except the tomatoes with the minced meat. Add the tomatoes and the pressed garlic clove. Season with salt, pepper, tomato paste and cocktail sauce. Let simmer in a closed pot for 10 minutes.
Mix in the egg yolk and butter under the mashed potatoes. Grease refractory form. Pour in the minced meat mixture. Cover with mashed potatoes. Place in the oven preheated to 225 ° C (gas mark 4) on the upper rail. Bake for 30 minutes.