Grilled Chicken Sandwich

Bahan-bahan (4 porsi)

• 1 ½ pounds boneless skinless chicken breasts (about 4 small breasts)
• 4 hamburger buns (or brioche rolls)
• ¼ cup honey mustard sauce (* or mayonnaise)
• toppings as desired (see notes)
• 3 tablespoons vegetable oil
• 2 tablespoons apple cider vinegar
• 1 tablespoon Dijon mustard
• 1 tablespoon brown sugar
• 1 teaspoon garlic powder
• ½ teaspoon salt
• ½ teaspoon black pepper