Strong coffee pairs with soy sauce and lightly caramelized garlic and onions in a marinade that leads to ultra-juicy flank steak.
- 4 tbsp. unsalted butter
- 8 cloves garlic, roughly chopped
- 1 large yellow onion, roughly chopped
- 1 cup strong coffee
- 1 cup soy sauce
- 1⁄4 cup Worcestershire sauce
- 3 tbsp. white vinegar
- 1 tbsp. crushed red chile flakes
- 1⁄2 tbsp. dried oregano
- Kosher salt, to taste
- 1 (2-lb.) flank steak
Melt butter in a 12" skillet over medium-high heat. Add garlic and onions; cook until slightly caramelized, 12–15 minutes, and transfer to a bowl. Whisk in coffee, soy, Worcestershire, vinegar, chile flakes, oregano, and salt. Reserve 1 cup marinade. Add steak to bowl; cover with plastic wrap and refrigerate overnight.
Heat a charcoal grill or set a gas grill to high; bank coals or turn burner off on one side (see Grilling 101). Remove steak from marinade and grill, flipping once, until browned, about 10 minutes. Using a brush, baste with reserved marinade, turning as needed until cooked to desired doneness, 15–20 minutes for medium rare. If outside starts to burn before steak is cooked, move to cooler section of grill until done. Rest steak 10 minutes; slice thinly on the bias.