Scalloped Ham and Potatoes

3/4 lb fully cooked boneless ham, cut into 1/2-inch chunks
1-26 oz pkg frozen shredded hash brown potatoes, thawed
2-10 oz cans condensed cream of celery soup
1-10 oz pkg frozen peas
1 1/2 C milk
1/4 tsp black pepper

Preheat oven to 350 degrees. Coat a 9 x 13-inch baking dish with cooking spray. In a large bowl, combine all ingredients; mix well then pour into prepared baking dish and cover tightly with aluminum foil. Bake 30 minutes then uncover and bake 50 to 60 more minutes, or until potatoes are tender and the top is golden.