Combine bouillon cube and cottage cheese, let stand 5 minutes.
Stir in Parmesan cheese.
Beat egg whites until soft peaks form, fold into cottage cheese mixture.
Cut tomatoes in half, place cut side up in a 13- x 9- x 2-inch baking pan.
Cover and bake at 350Â° for 5 minutes.
Spoon cottage cheese mixture over cut surface of tomatoes.
Broil tomatoes 5 inches from heat 3 to 5 minutes.