Mozzarella and Pepper Stuffed Portobello Bake

Ingredients

• 4 (2 oz. or 60 g) portobello mushrooms
• salt and pepper, to taste
• 1/2 medium (2 oz or 60 g) onion, chopped
• 2 (3 g) cloves garlic, minced
• 1/2 medium (2 oz or 60 g) red bell pepper, chopped
• 1/2 cup (2 oz or 60 g) shredded mozzarella
• 1 tablespoon (15 ml) olive oil
• cooking oil spray