In a bowl mix together the beef, breadcrumbs, milk, Worcestershire sauce, cinnamon, salt, and pepper until fully combined. Then form into even sized balls.
Preheat a saute pan on medium heat. Once hot, add the oil. Brown the meatballs well on all sides. Transfer the pan to the oven and cook to an internal temperature of 150 degrees using a thermometer.
For the sauce: place sugar, water, vinegar, soy sauce, cornstarch, and ketchup in a medium saucepan and bring to a simmer. Stir continuously until mixture has thickened to a smooth consistency. Remove from the heat.
Toss the meatballs in sauce before serving. Serve with bread. Garnish with parsley.