Ingredients

1 pound lean ground beef
2 to 3 tablespoons all-purpose flour
1/2 cup prepared French onion soup
Yellow mustard
4 slices white bread
1 medium onion, cut into rings

Instructions

In a medium skillet over medium-high heat, brown
ground beef and drain. Return ground beef to skillet and sprinkle in 2 to 3 tablespoons flour. Add onion soup,
stir, and cook until meat mixture is thickened and most of the liquid is absorbed. Spread mustard on white
bread, spoon ground beef mixture onto bread and top with onion.