Vinegar-Braised Chicken and Onions

INGREDIENTS

• 2 cipolline or pearl onions
• Kosher salt
• 3 olive oil
• 8 pancetta (Italian bacon), cut into 1/4-inch pieces
• 4 garlic cloves, peeled, crushed
• 5 skin-on bone-in chicken pieces (breasts, thighs, and/or legs; breasts halved crosswise)
• Freshly ground black pepper
• 3/4 balsamic vinegar
• 3/4 red wine vinegar
• 2 low-sodium chicken broth
• 1/2 golden raisins
• 2 bay leaves