1/2 c. soy sauce (we use a light variety)
1/4 c. olive oil
2 tbsp. molasses
2 tsp. dry mustard
2 tsp. ginger
3/4 tsp. garlic

Mix together with a fork in a small bowl and pour over meat. 
Allow to marinate in the refrigerator for 2 or more hours before grilling.

For london broil grill just 3-5 minutes per side on medium heat.  When you remove the 
meat from the grill wrap it in foil and allow to stand at least 5 minutes before slicing.