3 tbsp. butter
2 tbsp. flour
1 tsp. salt
1/4 tsp. pepper
2 c. milk
3 (1 lb.) medium potatoes cut into 1/8" rounds
1 medium onion, chopped fine (1/2 c.)

Place butter in a 1 1/2 quart bowl. Microwave on high 30-45 seconds until melted. Stir in flour, salt and pepper until blended. Gradually whisk in milk until smooth. Microwave on high 8-10 minutes, stirring twice until boiling and slightly thickened. Lightly grease a shallow 2 quart casserole. Arrange half the potatoes in bottom, sprinkle with half the onion, then pour half of the white sauce on top. Repeat layers, cover with vented plastic wrap. Microwave on high 16-18 minutes rotating dish 1/2 turn once, until potatoes are tender and sauce is set around edges (center will be slightly loose.) Let stand 5 minutes or until sauce in center is set. Sprinkle with parsley.