Preheat toaster oven to 350°.
Place tomato halves on toaster oven pan coated with cooking spray. Sprinkle breadcrumbs over each tomato half, and top with cheese. Sprinkle with oregano and pepper. Bake at 350° for 20 minutes. Serve warm.
Note: To bake in a conventional oven, place tomato halves on a baking sheet. Bake at 350º for 25 minutes.