Carefully remove stems from mushrooms. Place the mushrooms stem side down onto a baking pan. Bake for 10 to 15 minutes until the water leaks out of them. Remove from the oven and using paper towels soak up excess water. Set aside.
Do not throw away the stems from the mushrooms but chop them up to be added to the stuffing.
In a skillet, heat the olive oil over medium heat. Add the chopped onion and garlic and saute for a couple minutes until the onion is translucent.
Add the green pepper and spinach to the skillet and cook for a couple more minutes. Add tomatoes, goat cheese, salt, pepper, mushrooms stems, hot sauce and breadcrumbs. Stir and cook for an additional couple minutes.
Stuff the mushrooms with the mixture equally. Top with mozzarella cheese.
Bake for about 10 minutes or until the cheese melts.
Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.