Peel, wash and chop the potatoes. Cook in boiling salted water for about 20 minutes. Wash the meat, dab dry and season with pepper. Heat oil in a pan and fry meat for 2-3 minutes on each side.
Drain the pineapple. Wash and halve the tomatoes. Boil up milk and butter. Drain potatoes. Add milk to the potatoes and mash to puree. Divide the mashed potatoes into 4 small ovenproof cups.
Put 1 slice of meat in each. Place pineapple slices and cherry tomatoes on top, sprinkle with cheese and season with coarse pepper. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 5-10 minutes until the cheese has melted.