Scalloped Potatoes #1

3 Tbsp margarine
1 small onion, minced
3 Tbsp flour
1 tsp salt
1-½ cup milk
1 cup shredded cheddar cheese
5 medium potatoes, sliced thin
¼ tsp paprika
*Preheat oven to 375˚, cook onion in margarine until tender. Stir in flour and salt. Cook 1 minute. Gradually add milk and cook stirring constantly till slightly thickened. Remove from heat and stir in 1/4 cup cheese. In shallow 2 qt. casserole arrange half of potatoes. Pour half of sauce on top. Sprinkle with half of remaining cheese. Repeat layers. Sprinkle with paprika. Bake covered for 45 min. Uncover and bake 15 more minutes or until potatoes are tender.