Directions

1. In a bowl, combine 2/3 of the garlic with 1/4 cup soy sauce, sesame oil, brown sugar, cumin, and red-pepper flakes. Thread 2 pieces of beef onto each of 16 skewers; arrange in a shallow dish. Pour marinade over beef; refrigerate covered 45 minutes or preferable overnight, turning once.
2. Meanwhile make dipping sauce: Heat canola oil in a small saucepan over medium heat. Add remaining garlic, cook, stirring, until soft, 3 minutes. Add broth and 1/4 cup water; bring to boil. Remove from heat; whisk in peanut butter, ketchup, vinegar, and remaining teaspoon soy sauce. Let cool completely.
3. Heat a grill to high. Season beef with salt and pepper. Remove skewers from marinade, letting excess drip off. Discard marinade. Grill beef 1 to 2 minutes per side for medium. Serve hot with dipping sauce on the side.