3 tbsp. butter
2 tbsp. flour
3/4 tsp. salt
1/4 tsp. pepper
2 c. milk

Place butter in 1 quart measuring cup. Microwave at 100% 1/2 minute or until butter is melted. Blend in flour and seasonings. Gradually stir in milk. Microwave at 100% 7 to 9 minutes, stirring every 4 minutes.

3 1/2 to 4 c. thinly sliced white potatoes
2 tbsp. minced onion

Layer half of potatoes, onion and sauce in greased 2 quart casserole. Repeat layers. Cover. Microwave at 100% 17 to 19 minutes, stirring after 10 minutes. Remove from oven and let stand covered 5 minutes before serving.