I clipped this easy recipe from the food section of a local newspaper many years ago. Although I'm not sure if it is actually German "style", it was so titled and is quite good! No condiment other than salt is added, so that the pure, rich, flavor of the butter is not altered. It can be eaten as is, but I usually put it on a bun - with no condiments!
Slowly melt butter in a medium skillet. Set skillet aside until butter cools slightly.
In large bowl, gently but thoroughly mix ground beef with plain or seasoned salt and 3 tablespoons of the melted butter. Form into 4 1-inch thick patties.
Add sliced onion to the skillet. Saute slowly until onion is tender; push onion to side of skillet. Add patties to skillet; raise heat to medium and cook until patties are browned on underside. Flip patties and cook to desired doneness, adding additional butter to skillet if needed. Do not flip patties more than once, and do not press patties down with spatula.
Serve patties surrounded and covered with the onions, or on a bun, if desired.