8 slices top round beef, about 4x6 inches in size and 1/4 inch thick (*see note) (ask your butcher), gently pound the slices with a meat mallet until they're a little thinner than 1/4 inch (be careful not to pound holes into them)
1/3 cup German yellow mustard
8 slices bacon
8 medium German pickles , sliced lengthwise
1 medium yellow onion , chopped
salt and freshly ground black pepper
For the Gravy:
1 tablespoon butter
1 tablespoon cooking oil
1 medium yellow onion , chopped
1 clove garlic , minced
1 small leek , chopped, rinsed and drained in colander
1 large carrot , chopped
1 large celery stalk , chopped
1 cup dry red wine
2 cups strong beef broth
1 tablespoon tomato paste
1 bay leaf
1 teaspoon sugar
1/2 teaspoon salt
1/4 teaspoon freshly ground black pepper
4 tablespoons chilled butter
cornstarch or flour dissolved in a little water for thickening (depending on how much gravy liquid there is you'll need about 1-2 tablespoons of cornstarch dissolved in 2-3 tablespoons of water or 2-3 tablespoons flour dissolved in 1/4 - 1/3 cup water)