¼ cup butter or margarine
¼ cup chopped onion
2 T all-purpose flour
½ tsp salt
1 ½ cups milk
2 egg yolks, beaten
1 tsp grated lemon rind
12 ounces peeled, deveined and cooked shrimp
1 can (4 oz.) sliced mushrooms, drained
Combine butter and onion in 2-quart microwave-proof casserole. Cook on high 2 ½ to 3 ½ minutes, or until onion is transparent. Stir in flour and salt. Cook on high 1 minute. Pour milk into 2-cup glass measure. Cook on high 2 ½ minutes, or until warm.
Stir into flour mixture. Blend until smooth. Cook on high 3 ½ to 4 minutes, stirring once during cooking time. Stir small amount into egg yolks; then pour egg mixture back into sauce. Blend well. Stir in lemon rind. Cook on medium-high for 2 ½ to 3 ½ minutes, or until thickened and hot, stirring every 2 minutes. Stir in shrimp and mushrooms. Cook on medium-high 2 to 3 ½ minutes.
Serve over rice or toast points.
To substitute fresh mushrooms for canned, combine with onion and butter and cook on high 6 to 8 minutes.