Mix together beef, bread crumbs, onion, margarine, salt, and
pepper. Beat egg until bubbly. Add 2/3 cups milk to meat mixture
and mix gently but thoroughly. Shape into 9x12" rectangle on wax
paper. Using paper to lift meat, roll into 9" cylinder. Place on a
shallow pan and bake at 350°F for 45 minutes. Prepare instant
potatoes. Add butter, onions, and salt to potatoes. Beat egg yolks.
Add milk to potatoes. Take meat loaf out of oven and frost with
mashed potatoes. Return to oven 10 minutes longer. Place cheese on
top and put under broiler until cheese melts.
