Grilled Root Beer Beef

Ingredients

• For the Marinade:
• 1 tablespoon vegetable oil
• 1 teaspoon freshly ground black pepper
• 1 teaspoon cayenne pepper
• 1/2 teaspoon ground chipotle pepper
• 2 tablespoons ketchup
• 1 teaspoon honey (optional)
• 1/3 cup soy sauce
• 2 tablespoons white vinegar
• 1 (12 fluid ounce) can or bottle root beer
• 1 (1 1/2-pound) flank steak
• skewers
• 1 teaspoon sesame seeds, or to taste