For the casserole peel and chop the onions. Clean and wash the peppers and mushrooms. Finely dice the bell peppers, halve the mushrooms. Remove 2 slices of bacon, dice the rest finely.
First fry the slices, then the cubes crisply in a pan without fat. Remove. Heat the oil in the bacon fat. Fry the mushrooms in it until they are well done. Briefly fry the bell peppers and onions (set aside 1 tbsp. onions for the side dish).
Season with salt and pepper. Sweat tomato paste and flour briefly. Stir in 100 ml water, cream and tomatoes, bring to the boil. Simmer for about 2 minutes. Season with salt, pepper, some sugar and paprika.
Grease an ovenproof dish (approx. 20 x 30 cm). Pat the roulades dry. Layer alternately with sauce and bacon cubes. Close the dish with foil. Cook in a preheated oven (electric cooker: 175 °C/circulating air: 150 °C/gas: see manufacturer) for approx. 2 1⁄4 hours. Remove the foil 30 minutes before the end.
Peel the potatoes for the side dish. Clean and wash the beans. Cut potatoes in half. Boil potatoes in salted water for about 20 minutes. Cook the beans in boiling salted water for 10-12 minutes.
Wash and chop the parsley. Fry the onion cubes in 1 tbsp. hot butter. Swivel with the beans. Drain potatoes and sprinkle with parsley. Arrange everything. Garnish with crispy bacon pieces.