Steak and Marinade:
3/4 cup vegetable oil
1/4 cup red wine vinegar
1/4 cup prepared chili sauce
2 teaspoon Worcestershire sauce
1/2 teaspoon salt
2 tablespoons fresh lemon juice
2 teaspoons seasoned salt
3 cloves garlic, minced
4-1/2 pounds beef flank steak
1 stick (1/2 cup) butter, softened
4 cloves garlic, minced
2 loaves French bread, split lengthwise
4 cups (16 ounces) Wisconsin muenster cheese, shredded
In a bowl, combine first 8 ingredients for marinade. Place steak in non-metal baking dish; pour marinade over steak. Cover and marinate overnight in refrigerator, turning occasionally. Let steak come to room temperature before grilling. Remove steak from marinade; drain off excess.
Combine butter and garlic; spread on cut bread. Sprinkle each half with 1 cup cheese. Cut 2 sheets of heavy foil to wrap 2 sandwich halves and spray each sheet with cooking spray. Wrap halves, loosely, side by side in foil, 2 halves per packet.
Set oven to broil. Place steak in broiler pan, 2 to 3 inches from top of oven. Broil 6 minutes each side. Remove steak, rest 10 minutes. Put bread in oven on middle rack. Broil 8 minutes or until cheese melts.
Slice steak thinly, across the grain. Remove bread. Top grilled bread with sliced beef, serving open-face. Cut each loaf into 6 pieces. Optional: garnish with cheese. Serve immediately.