Hot And Spicy Spareribs

• 2 garlic (cloves minced)
• 1 rack pork spareribs
• 1 onion (finely chopped)
• 425 ml tomato sauce
• 160 ml cider vinegar
• 150 gr firmly packed brown sugar
• 28 gr butter
• 18 gr chili powder
• 16 ml prepared mustard
• 1 gr pepper