I believe “instant minced onion” is freeze-dried onion pieces.
A family recipe provided by Jennifer Kiel of Washington, DC, from her mother-in-law’s collection, started in Kent, Ohio.
Zippy Beef Casserole
1 lb. ground beef
1 cup uncooked macaroni
1 can cream of mushroom soup
3/4 cup milk
2/3 cup catsup
1/2 cup shredded Cheddar cheese
1/4 cup chopped green pepper
1 to 2 Tbsp. instant minced onion
1 tsp. salt
1 cup crushed potato chips
Brown meat, stirring until brown. Drain off excess fat. Cook macaroni; drain. Combine all ingredients except potato chips in a 2 qt. casserole. Cover, bake 40 minutes in a 350 degree oven. Uncover, sprinkle with potato chips and bake 5 minutes longer. 4 to 6 servings.