Beat eggs in separate dish. Mix ground beef and sausage together. Add ketchup, horseradish mustard, garlic and onion powder, and diced onions. Mix, by hand, until well blended. Add eggs and onions. Continue mixing until well blended. Roll into 4 big patties (or 6 medium). Starting from center, flatten out by hand and place in a cool skillet. Cook on medium low turning several times for even cooking. Do not flatten them with the spatula. Serve with or without brown gravy with your favorite side dishes.