1.Blend onion, ginger, jalapeno, garlic, mustard, spices and liquids in a blender or food processor fitted with a steel blade until mixed. 2.Place steak in a sealable plastic bag and pour marinade over steak. Seal well and refrigerate 20 min to 6 hours, turning bag occasionally. Remove meat from bag, reserving marinade. 3.Grill steak 4 to 6 inches from medium coals for 16 to 20 min., turning once. Remove steak to carving board; let stand 10 min. 4.Meanwhile, bring reserved marinade to a rolling boil in a small saucepan over medium-high heat. Reduce heat and simmer 2 to 3 min. 5.Carve steak diagonally into thin slices. Arrange on a platter and serve with heated sauce. Garnish with lime wedges, cilantro sprigs and jalapenos if desired. Serving Suggestion: Island Black Beans, Caribbean Rice, Red Hot Onion, Fruit Kabobs of pineapple, strawberries, kiwi & mango, Jamaican Peppered Corn Bread and Key Lime Pie. Note: This marinade is excellent for basting grilled beef back ribs, marinating beef briskets or for braising beef short ribs.