Beer-Marinated Flank Steak

1 large onion, chopped
1/2 teaspoon ground cumin
4 garlic cloves, finely minced
1/2 teaspoon salt
Freshly ground pepper to taste
1 (12-ounce) bottle beer
1 (1 1/2-pound) flank steak

1. Combine all ingredients except steak in a large self-closing
   plastic bag, mixing well. Add steak to marinade, seal and
   refrigerate for 12 hours or overnight.
2. Remove steak from marinade. Broil 5-inches from heat for 4 to
   5 minutes on each side, or until desired degree of doneness.
3. To serve, thinly slice steak diagonally across the grain