For the meatballs:
1 1/2 pounds ground beef
3/4 cup quick oats
1 cup milk
3 tablespoons very finely minced onion
1 1/2 teaspoons salt
Freshly ground black pepper
4 tablespoons canola oil
1/2 cup all-purpose flour
For the Sauce:
1 cup ketchup
4 to 6 tablespoons minced onion
3 tablespoons distilled white vinegar
2 tablespoons sugar
2 tablespoons Worcestershire sauce
Dash of hot sauce, such as Tabasco
For the meatballs: In bowl, combine the ground beef and oats. Pour in the milk, and then add the onions, salt and pepper. Stir to combine. Roll the mixture into tablespoon-size balls and refrigerate them for 30 to 45 minutes to firm.
Preheat the oven to 350 degrees F.
Heat the canola oil in a large skillet over medium heat. Dredge the meatballs in the flour, and then brown the meatballs in batches until light brown. As they brown, place them into a rectangular baking dish.
For the sauce: Stir together the ketchup, onions, vinegar, sugar, Worcestershire sauce and hot sauce. Drizzle the sauce evenly on the meatballs.
Bake until bubbly and hot, about 45 minutes.
Source: Pioneer Woman