Cut the tomatoes in half, horizontally. Seed by gently squeezing the tomato halves. Use a small spoon to gently hollow out the inside of the tomatoes, being careful not to puncture the outer shell. Reserve the pulp.
Chop the reserved pulp and put in a medium bowl. Add the parsley, bread crumbs, cheese, optional garlic, and pepper and mix gently to combine.
Place the tomato halves in a buttered casserole dish, and fill with the bread crumb mixture.
Drizzle the top of the tomatoes with olive oil. Bake until the tops are browned, about 20 minutes.