Cut the garlic and mushrooms into thin slices. In a hot pan, briefly fry the mushrooms in portions in olive oil, then keep warm in the preheated oven.
Now sauté the garlic in the butter and deglaze with lemon juice. Stir in tomato paste and season with salt and pepper. Stir in the mushrooms and cook in an ovenproof dish for 10 minutes. Sprinkle with the mint and serve hot.