Brush off the mushrooms, unscrew the stems and scrape out the lamellas with a teaspoon. Sauté the diced onion with the diced mushroom stalks in olive oil and then deglaze with lemon juice.
Now add the coarsely chopped spinach and the crumbled sheep`s cheese and heat briefly. Before the mass is poured into the mushrooms, season with salt and pepper, if you also like with garlic.
Now put the mushrooms in a greased, fireproof dish, cover with a little butter and breadcrumbs and bake at 180 degrees (preheated) for 20 minutes until golden yellow.
A salad with vinaigrette and baguette goes well with it.