1. Combine olive oil, vinegar and garlic in a small bowl.
2. Brush both sides of mushrooms with mixture until all is used.
3. Preheat oven to 375°F.
4. Combine Ricotta, Parmesan cheeses and basil till blended.
5. Place slice of tomato on the gill or stem side of mushroom on a baking sheet.
6. Mound all of the cheese mixture on tomatoes.
7. Top with cheese slices.
8. Bake for 30 min or until cheese is melted and golden.

* To make vegan replace Ricotta cheese with vegan ricotta or medium-firm tofu, use vegan parmesan, and use vegan cheese slices.