Soak rolls in cold water. Peel onions and garlic and dice finely. Squeeze the bread roll well. Knead with minced meat, half of the onions, garlic, 1 tablespoon tomato paste and egg.
Season with salt and pepper. Divide the minced meat into 12 portions, shape slightly oblong. Place on 1 slice of ham and roll up. Peel, wash and cut the potatoes into pieces. Cook in boiling salted water for about 20 minutes.
Clean and clean the mushrooms and cut them into slices. Heat the oil in a pan, fry the mushrooms in portions all around, place in a greased casserole dish. Bake in a preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 15 minutes.
Sauté the mushrooms in hot frying fat. Add remaining onions and oregano and fry briefly. Add 2 tablespoons of tomato paste and sauté briefly. Deglaze with 150 ml water and cream, simmer for about 5 minutes.
Drain the potatoes and let them drain. Heat milk and 25 g butter, add to the potatoes and mash everything to a puree. Season to taste with salt and nutmeg. Season the sauce with salt and pepper.
Spread over the package. Gratinate under the hot grill for 1-2 minutes. Serve garnished with oregano.