Preheat oven to 325°F. Place parsley, garlic, pepper and 1 tablespoon olive oil in food processor or blender container. Cover; process until just blended. Rub mixture evenly over all surfaces of roast. Place roast, fat-side up, on rack in shallow roasting pan. Insert ovenproof meat thermometer so tip is centered in thickest part of beef. Do not add water or cover. Roast in 325°F oven 60 to 75 minutes for medium rare to medium doneness.
Toss tomatoes with remaining 1 tablespoon olive oil in large bowl. Arrange tomatoes, cut sides up, on metal baking sheet. Roast in 325°F oven for 1 hour or until skins are wrinkled and begin to brown.
Remove roast when meat thermometer registers 135°F for medium rare; 150°F for medium. Transfer roast to carving board; tent loosely with aluminum foil. Let stand 10 minutes. (Temperature will continue to rise about 10°F to reach 145°F for medium rare; 160°F for medium.) Meanwhile, increase oven temp to 425°F. Sprinkle tomatoes with Parmesan cheese. Continue roasting an additional 8 to 10 minutes or until cheese is melted and tomatoes are lightly browned. Season with salt and pepper, as desired.
Carve roast into slices; season with salt and pepper, as desired. Serve with tomatoes.