Brown Sugar Chicken

Season chicken on both sides with salt and pepper. In a large skillet over medium heat, heat olive oil. Add chicken and let cook until golden and cooked through, 8 minutes per side. Remove from pan. Add butter to pan then add chicken broth and garlic and cook until fragrant, about 1 minute. Add brown sugar, mustard, rosemary, and red pepper flakes. Stir until brown sugar is melted and a sauce forms. Add back chicken and spoon sauce over chicken.