Good Scalloped Potatoes

6 potatoes, peeled and cut into 1/2-inch rounds

1 tablespoon olive oil

1 small onion, chopped

1 (10.75 ounce) can condensed cream of mushroom soup

1 cup grated Cheddar cheese

1 (5 ounce) can evaporated milk

Preheat oven to 350 degrees F (175 degrees C).

Place potatoes into a large pot and cover with salted water; bring to a boil. Reduce heat to medium-low and simmer until slightly tender, about 5 minutes. Drain.

Heat olive oil in a skillet over medium heat; cook and stir onion until lightly browned and tender, 10 to 15 minutes.

Mix onion, cream of mushroom soup, Cheddar cheese, and evaporated milk in a bowl. Arrange potatoes in a 9x13-inch casserole dish. Pour sauce over potatoes.

Bake in the preheated oven until potatoes are tender and sauce is bubbling, 20 minutes.