Sweet Onion Casserole

INGREDIENTS

• 1 tablespoon canola oil
• 4 cups chopped sweet onion (about 1 3/4 pounds)
• 1/2 cup uncooked long-grain rice
• 2/3 cup 2% reduced-fat milk
• 1/2 cup (2 ounces) shredded Gruyère cheese
• 1/4 teaspoon salt
• 1/4 teaspoon freshly ground black pepper
• 1/8 teaspoon ground allspice
• Cooking spray
• 1/3 cup (1 1/3 ounces) grated Parmesan cheese
• 2 tablespoons chopped fresh parsley (optional)