Creamy Hash Brown Bake

1 tbsp. margarine
1/2 cup chopped onion
1 10 oz. can of condensed cream of chicken soup (or one recipe of cream soup substitute - see next blog post for recipe)
1/2 cup milk
4 oz. block of cream cheese, softened and cut up
pinch of salt
1/4 tsp. pepper
1 kg. package of frozen hash brown potatoes, partially thawed
1 cup grated cheddar cheese

Melt margarine in large saucepan on medium. Add onion. Cook for 5 to 10 minutes, stirring often, until softened. Add soup and milk. Stir. Add next 3 ingredients. Heat and stir for 3 to 4 minutes until cream cheese is melted. Add hash brown potatoes. Stir until coated. Spread evenly in greased 2 quart (2L) casserole. Cover. Bake in 350 degree oven for about 1 hour until edges start to brown. Remove from oven. Sprinkle with cheddar cheese. Bake uncovered for another 10 minutes until cheese is melted. Serves 6.