Clean the mushrooms, rub them and cut them into smaller pieces. Peel onion, cut into rings. Cut bacon slices in half and fry them in a pan without fat. Take out.
Fry the mushrooms and onion in the frying fat. Season with salt and pepper. Wash herbs and chop finely. Mix with sour cream and season with a little salt.
Spread on the bread. Cover with mushrooms and bacon. Spread cheese over it. Bake in the preheated oven (electric cooker: 225°C/circulating air: 200°C/gas: 4) for 7-10 minutes.