Vegetarian Recipe: Baked Button Mushroom Posted by Susan Siow | Sep 3, 2011 | Updates, Vegetarian Recipes, Western Ingredients 1 packet of button mushrooms (slice) 1/2 teaspoon of oil Seasonings some salt Method Lay sliced mushrooms on a baking tray. Sprinkle over salt + oil. Put in a 180°c oven and bake for about 15 minutes. Serve.