Spray a 9x13 inch pan with non-stick cooking spray.
Line the bottom of the pan with hashbrowns.
Brown the hamburger and onions; drain.
Mix 1 can cream of mushroom soup with half can of milk; then add the hamburger and onions.
Spoon the soup-hamburger mixture on top of the hashbrowns.
Top with frozen peas.
Cover with American cheese slices.
Cover with foil. COOK’S TIP: Spray the foil with no-stick spray to prevent cheese from sticking.
Bake at 350 degrees for 50 minutes.
Take off the foil, cover with French fried onions and bake uncovered for another 10 minutes.
Let it rest for 5 minutes on the counter before serving.
