Scalloped Potatoes - cooking recipe

Ingredients

1/4 c. butter
4 medium potatoes, sliced 1/8-inch thick
1/4 c. flour
1 tsp. salt
2/3 c. chopped onion
1/4 tsp. pepper
2 c. milk
2 c. shredded Cheddar cheese

Preparation

Melt butter in 1-quart saucepan over medium-low heat.
Whisk in flour, salt and pepper.
Cook, stirring 1 minute.
Gradually whisk in milk.
Cook and stir until sauce is smooth and thickened, 3 to 4 minutes.