Peel and chop onion and garlic. Sauté in 1 tbsp. hot butter. Add spinach and 2 tablespoons of water. Cover and cook over medium heat for 10-15 minutes. Seasoning
Meanwhile clean the mushrooms, cutting the stems only flat. Fry the bacon in an ovenproof pan until crispy, drain. Heat the oil in the bacon fat. Fry the mushrooms for about 5 minutes, turning them over. Season with salt and pepper
Mix 1/8 l water and sauce powder, bring to the boil. Remove from the heat and fold in 125 g butter in pieces
Fill mushrooms with spinach. Spread cheese and sauce over it. Bake under the hot grill or in the oven at high heat for about 3 minutes. Halve the bacon, spread on top