1 lb. very lean, double ground round steak
1 lg. egg yolk
1/2 c. finely diced, white sweet onion
1/4 c. white vinegar
3 tbsp. Mazola oil
1 tsp. sugar
1/2 tsp. pepper
Dash of salt

In medium bowl, mix ground round steak, egg yolk, onion, salt and pepper. Mix oil, vinegar and sugar together and add to beef. Spread thin layer of beef mixture on lightly buttered German pumpernickel, or party rye bread, cut in quarters. For a tangier taste, you may add finely chopped pimento, or 2 tablespoons capers.