1. Mix molasses and vinegar. Pour 1/4 cup into a 2-gallon food bad. Add ribs; turn to coat. Refrigerate at least 4 hours.
2. Heat oven to 325°F. You’ll need a foil-lined roasting pan with a rack.
3. Place ribs on rack. Sprinkle with 1 tsp each salt and pepper. Cover with foil; bake 1 1/2 hours. Meanwhile, in saucepan, simmer remaining molasses mixture 5 minutes or until slightly thickened.
4. Brush ribs with mixture; bake, uncovered, 1 to 1 1/2 hours until tender. Cut to seperate individual ribs; drizzle with remaining molasses mixture