Prep: 1. Place ribs in a roasting pan, cutting racks in half to fit if necessary. 2. Mince garlic. 3. Chop rosemary. 4. Combine garlic, rosemary, brown sugar, 1 tablespoon balsamic vinegar, 1 1/2 teaspoons salt and cayenne in a bowl, and rub mixture evenly all over ribs. 5. Allow ribs to marinate in refrigerator for at least 1 hour and up to 4 hours. Make: 1. Place a rack in center of oven and preheat the oven to 425. 2. Pour 1/2 cup water into roasting pan and cover pan tightly with aluminum foil. 3. Roast ribs until meat is very tender and separate easily from bone, about 1 1/2 hours. 4. While ribs are roasting make BBQ sauce, place 1 cup balsamic vinegar in a saucepan over medium-high heat. 5. Bring to a boil then lower heat to medium and cook vinegar until it is reduced by a third, ~8 minutes. 6. Whisk in ketchup, apple cider vinegar, honey, mustard, molasses, Worcestershire, hot sauce and 1/4 teaspoon salt. 7. Bring sauce back to a boil then lower heat and simmer until thickened, 15-20 minutes, stirring occasionally. Remove from heat and let cool to room temperature. 8. To finish, remove ribs from oven and transfer to 2 aluminum-foil-lined baking sheets. 9. Increase oven temperature to 450. 10. Brush both sides of ribs generously with the homemade BBQ sauce and bake uncovered for 10 minutes, until sauce is browned and sizzling. 11. Allow ribs to rest for 10 minutes before slicing.