Cook 6 slices of the bologna in a skillet until the center puffs up, about 1 minute.Put bologna cups in lightly greased muffin cups. Chop the remaining 2 slices of bologna. In a small bowl, beat together eggs and milk. Stir in the chopped bologna and onion. Pour egg mixture into bologna cups. Bake, uncovered, in a (375F) oven for 15 to 17 minutes or until eggs are set. Sprinkle with the cheese. Bake for a couple minutes longer, until cheese melts.