Peel and wash the potatoes and cook them in boiling salted water for about 20 minutes. Peel and finely chop 1 onion and garlic. Melt the fat in a saucepan. Fry onion and garlic in it and put aside. Clean and wash the tomatoes and cut off a lid. Peel 1 onion and chop finely.
Hollow out the tomatoes to a 1 cm wide edge. Chop tomato lid and flesh finely. Season with salt, pepper and marjoram, add onion. Place everything in a large casserole dish. Drain the potatoes. Add milk and onion-garlic mixture to the potatoes and mash. Season to taste with salt and pepper. Season tomatoes with salt and pepper. Fill garlic-potatoes into the tomatoes and press a hollow into each. Put the tomatoes into the mould. Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20-25 minutes. 10 minutes before the end of the cooking time, break open the eggs and place each egg in a recess. Cover with bacon slices and continue cooking.
Season to taste with salt and pepper. Season tomatoes with salt and pepper. Fill garlic-potatoes into the tomatoes and press a hollow into each. Put the tomatoes into the mould. Cook in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20-25 minutes. 10 minutes before the end of the cooking time, break open the eggs and place each egg in a recess. Cover with bacon slices and continue cooking. Arrange "ox hearts" with the stock on small plates. Garnish with marjoram