Creamy Mushroom Scalloped Potatoes

I took my Grandmother's old recipe for
baked scalloped potatoes and added
a can of cream of mushroom soup to the mix.
This turned out better than I had anticipated.
This is a good one!

Ingredients:
6 medium potatoes, peeled and sliced thin
1 can condensed cream of mushroom soup
4 ounces (1 cup) grated cheddar cheese
1/4 teaspoon fresh ground black pepper
4 medium onions, peeled and sliced
1 teaspoons salt or to taste
1 cup milk

Directions:
Preheat oven to 350 degrees F.
Lightly grease a 2-quart casserole dish.
Mix soup, salt, pepper and milk together.
In the prepared casserole dish,
place half of the potatoes in a layer
and then half of the onions.
Pour half of soup mixture over potatoes and onions.
Repeat layers with the remaining potatoes, onions and soup.
Sprinkle grated cheese on top. Bake uncovered for about 1-1/2 hours.