Wash potatoes thoroughly and cook in boiling water for about 25 minutes. Drain, quench, peel, let cool slightly and cut into slices
Meanwhile wash the meat and pat dry. Heat 2-3 tablespoons of oil in a large frying pan and fry the meat for about 12 minutes. Season with salt and pepper, remove from the pan and leave to rest for approx. 10 minutes
Peel and finely chop the onion. Add the diced bacon to the pan and leave it out. Take off approx. 1 tbsp. Add 1 tbsp. oil to the pan, add onion and fry until translucent. Add tomato puree and herbs and sauté briefly. Deglaze with tomatoes, stock and cream. Season with salt, pepper and paprika. Bring to the boil and simmer for about 5 minutes
Grate cheese. Wash the rosemary, shake dry and pluck the needles from the twigs. Put almost 1/3 of the potato slices in a greased baking dish. Place the remaining potato slices close together in a fan shape on the edge of the baking dish. Cut the meat open. Distribute in the middle of the casserole dish. Pour the sauce evenly over the meat. Sprinkle with rosemary. Sprinkle with cheese and diced ham. Bake in the preheated oven (electric range: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20-25 minutes. Remove from the oven, garnish with oregano