Add the mushroom caps to a large storage bag (use a reusable storage ... My favorite way to reheat leftover grilled portobello mushrooms is in the oven. Preheat the oven to 350°F and heat them on the ...

portobello mushrooms are often cooked whole, whether that's grilled, baked, or stuffed. Each part of the mushroom is edible, including the large cap, dark gills, and lighter colored stem.