For the gravy (we didn't use it):
Melt the butter in a frying pan.Cook onions in the butter until clear.Soak the bread in milk.
Combine all the ingredients in a large bowl and mix well. Form meat into balls about the size of a golf ball.
Melt about 1 tbsp butter in a pan and there brown the meatballs on all sides or (like we've done) place the meatballs on a baking dish previously covered with baking paper
and bake them on a previously pre-heated oven at 180°C for 30 minutes or until well done.
For the gravy cook the flour in a pan with the fat resultant from the frying and then add the beef stock stirring continuosly for avoiding lumps.
Cook the gravy until it's thick.
Serve the meatballs with mashed potatoes and lingonberry jam.