Vegetarian Stuffed Portobello Mushrooms

Name: Vegetarian Stuffed Portobello Mushrooms
Ingredients: 2 small yellow squash, thinly sliced; 2 small zucchini, thinly sliced; 2 small green bell peppers, thinly sliced; 1 small onion, thinly sliced; 3 tablespoons olive oil, divided; 1 tablespoon balsamic vinegar; 3 tablespoons garlic and herb seasoning blend (such as Mrs. Dash®); 4 large portobello mushroom caps; 1 cup shredded Parmesan cheese; 1.5 cups shredded mozzarella cheese; 1 tablespoon chopped fresh parsley; 0.25 cup pineapple chunks