Combine all meatball ingredients except the oil in a large mixing bowl. Using clean hands, mix together ingredients just until thoroughly combined. Form meatballs into 2-inch (golfball size) balls.
Heat oil in a large stockpot over medium high heat. Reduce heat to medium. Working in batches, add the meatballs and brown on all sides, about 2-3 minutes. Remove meatballs from the pan and set aside.
Melt butter in the stock pot. Add the onions and cook until they being to soften, about five minutes. Season onions with salt and pepper. Pour in the stout and the sugar. Add the meatballs back to the pot. Bring pot to a boil, then reduce heat to low. Simmer, covered, until meatballs are cooked through, about 20 minutes. Remove lid from pan and cook an additional 10-15 minutes or until the sauce has reduced and thickened.
Stir in remaining two tablespoons of butter.
Served over hot buttered egg noodles drizzled with onions and gravy.