Marmalade Glazed Pork Roast

INGREDIENTS

• 1 (2 1/2 pound) boneless pork loin roast
• salt and ground black pepper to taste
• 1/2 cup orange marmalade, divided
• 1 tablespoon chopped fresh rosemary
• 1/2 cup orange juice
• 1 tablespoon olive oil
• 1 pound parsnips, peeled and cut into 1-inch wedges
• 2 red onions, cut into 1-inch wedges