Sweet and Sour Potted Meatballs

Ingredients

• 2 tbsp. canola oil
• 1 medium yellow onion, minced
• 1 (15-oz.) can tomato sauce
• 1⁄2 tsp. sour salt; or the juice of 1 lemon (about 2 tbsp.)
• 1⁄4 cup firmly packed dark brown sugar
• Kosher salt
• freshly ground black pepper
• 2 lb. ground beef chuck
• 2 eggs, beaten
• 1⁄3 cup long-grain white rice, parboiled for 3 minutes
• 1 cup bread crumbs
• 1 medium yellow onion, grated on the coarse side of a box grater
• 2 1⁄4 tsp. kosher salt
• 1⁄2 tsp. freshly ground black pepper