Sort the spinach, wash thoroughly and drain. Clean the oyster mushrooms and, depending on their size, possibly halve them. Drain the pickled peppers and cut them into pieces of approx. 3 cm.
Peel onions and garlic. Chop the onions finely, press the garlic through a garlic press. Heat oil in a pot and fry 2/3 of the onions in it. Cut the canned tomatoes roughly into pieces with a long knife and add to the onions.
Stir in tomato paste, pour in broth and season with salt, pepper and oregano. Bring sauce to the boil and simmer for about 10 minutes. Meanwhile heat 10 g fat in a pot, add remaining onions and half of the garlic and braise.
Add the spinach and cover and allow to collapse. Season with salt, pepper and nutmeg. Heat the remaining fat in a pan and fry the oyster mushrooms until crispy brown. Finally add the remaining garlic, fry briefly and season with salt and pepper.
Deglaze with vinegar. Put the pasta in plenty of boiling salted water and boil for 4-5 minutes until it becomes bubbly. Pour onto a sieve, rinse under cold water and drain. Grease a baking tray or 4 small portion gratin dishes well.
Make little nests from the noodles and layer them alternately with spinach, mushrooms and peppers to form little towers. In between always add some tomato sauce. Finish with a spoon of tomato sauce and sprinkle with cheese.
Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for approx. 5 minutes. Serve with remaining tomato sauce.