8 1/2 lb. swordfish steaks, about 1 inch thick
1/4 c. fresh lemon juice
5 tbsp. Dijon mustard
1/4 c. butter (1/2 stick)

MUSTARD SAUCE:

6 tbsp. butter, melted (3/4 stick)
3 tbsp. fresh lemon juice
2 tbsp. Dijon mustard

Prepare barbecue grill with very hot coals. Pat fish dry. Brush with lemon juice, spread 1 side with mustard. Dot with butter. Grill fish mustard side up until just opaque, about 20 minutes; do not turn. Heat butter, lemon juice, and mustard in heavy saucepan. Arrange fish mustard side down on plate. Spoon sauce over and serve.