Combine meat, egg, onion, salt and pepper in large mixing bowl.
With wooden spoon, work in flour; add milk last, a little at a time.
Let stand about 10 minutes.
In heavy skillet, melt 3 tbs butter or margarine; when light brown, turn heat to low.
Form meat balls, with large tablespoon, & brown on all sides.
Fill pan and cook over medium heat for 15 minutes, or bake in oven, 325 degrees, for 30 minutes.
Very good served with creamed cabbage, creamed spinach and small, boiled potatoes.