- Stir together all ingredients except ribs in a medium bowl until brown sugar is thoroughly mixed. Remove ⅔ cup of sauce mixture and set aside. Add remaining sauce to the bottom of slow cooker. Add ribs and use hands to coat in sauce on both sides. Cook on high for 4 hours (or on low for 6-8 hours). Flip ribs using tongs halfway through cooking.
- Pour reserved sauce in a saucepan and heat over medium-low heat until bubbling. Reduce heat to low and simmer until brown sugar is dissolved, 5-7 minutes. Pour into a small bowl and set aside.
- Position oven rack to center and heat oven broiler on high. Remove ribs from slow cooker and place on a medium baking sheet lined with aluminum foil. Brush ribs with reserved sauce. Broil for 6-8 minutes, until sauce is caramelized. Rest ribs for 10 minutes tented with aluminum foil before slicing.