Leftover Roast Beef Casserole

lb leftover roast beef – cubed or shredded
1 med yellow onion – diced
1 cup frozen corn
1 cup frozen peas
(1) 10.75 oz can cream of celery soup
1/2 cup milk
1 lb diced cooked potatoes
1/2 tsp salt
1/2 tsp pepper

• Preheat oven to 350 degrees. 

• In a large mixing bowl combine all ingredients and mix thoroughly. 

• Transfer mixture to a 1 1/2 quart casserole dish 

• Bake uncovered at 350 degrees for 45 minutes.