Wash and dry the tomatoes and cut in half, cross-wise. Place tomatoes cut-side up on a rimmed baking sheet. Mix the grated parmesan, thyme, bread crumbs, salt and pepper together in small bowl. Sprinkle this mixture on tomato tops, drizzle with olive oil and top with the shaved Parmesan (this is optional). Bake for about 10-15 minutes until nice and brown.