Escalloped Potatoes
["4 c. thinly sliced potatoes", "2 Tbsp. finely minced onion", "salt to taste", "1/4 c. (1/2 stick) butter", "2 Tbsp. flour", "2 c. milk", "1 tsp. salt"]
["Peel and slice potatoes thin.", "Arrange in alternate layers with onion in a 1 1/2-quart casserole, salting each layer slightly.", "Melt butter in a saucepan; add flour and blend.", "Add milk and cook and stir until smooth and thickened.", "Add salt and blend.", "Pour over potatoes; cover casserole and bake in a moderate 350\u00b0 oven for 30 minutes; then uncover and continue to bake for 25 or 30 minutes longer or until potatoes are tender and lightly browned on top."]
["potatoes", "onion", "salt", "butter", "flour", "milk", "salt"]