Cook broccoli in a shallow, heat-resistant, non- metallic, 1 1/2-quart baking dish. Drain and set aside.
In a small, heat-resistant, non-metallic bowl melt butter or margarine in Microwave Oven 30 seconds.
Blend in flour with a fork until smooth. Gradually stir in milk. Heat, uncovered, in Microwave Oven 1 minute or until thickened and smooth.
Gradually stir in lemon peel and juice so that the mixture does not curdle. Stir in salt and ginger until well blended.
Spoon sauce over drained broccoli spears. Heat, uncovered, in Microwave Oven 1 to 2 minutes or until heated through.