In crock pot layer ham, onions, sliced potatoes, cheddar cheese, salt, and pepper. Repeat layers.

In frying pan, melt 2 tablespoons butter until it bubbles. Add 2 tablespoons flour. Stir until brown. Add 2 cups milk. Stir until thickens.

Pour mixture over layers in crock pot. Cook on low all day or until potatoes are done.