In case you have an oven safe pot, preheat oven to 320° F or 160° C. If not, see below for alternative method.
1 ½ pounds beef steak
Rinse and pat dry your steak. Cut into 8 pieces, then flatten each piece by putting it in a gallon-sized freezer bag and hammering it with the flat side of a meat hammer.
Cut onions in half, then slice. Cut bacon slices in half. Prepare your twine and keep scissors handy. You can also use toothpicks instead of the twine.
4 yellow onions, 40 dill pickle chips
Spread a thin layer of mustard on the meat, season with salt and pepper. Cover with a generous amount of onion slices, about 5 pickle chips, and 1 slice of bacon.
8 teaspoons mustard, 4 yellow onions, 40 dill pickle chips, 8 slices bacon, 1 ½ pounds beef steak
Roll up and tie up with twine or secure the seams with toothpicks. Add butter to a large skillet and heat to medium high.
30 grams butter
Sauté the Rouladen for a few minutes on all sides, until browned. Transfer to a large pot (oven safe if possible).
Medium dice the celery, the onion, carrot. Slice the leek. Add to the skillet you transferred the meat from.
1 stalk celery, 1 leek, 1 carrot
As soon as they start yellowing in color, add a thin layer of red wine. Let the wine evaporate and refill with a thin layer of wine. Repeat until you used half a bottle. This will help develop a deeper flavor. Add salt, pepper, broth and pickle juice. Alternatively, you can also use beer! Beer gives it a different, wonderful flavor. I personally prefer the wine sauce, but they're both amazing options!
375 milliliter red wine, 500 milliliter beef stock, 75 milliliter pickle juice
Add everything to the Rouladen. If the pot is oven safe, cover it with a lid and put in the oven for about 90 minutes. If it's not oven safe, cover and cook on your cooktop on medium-low heat instead.
If needed, add more broth about every 30 minutes or so. After 90 minutes, test to see if the roulades are tender (use a cooking spoon to gently press down on one). If not tender, cook for another 30 minutes (they may take even longer if using top-round steak). If they're tender, carefully remove them using tongs and keep them warm.
500 milliliter beef stock
Strain the sauce and bring to a boil. Whisk together 1 tablespoon of mustard, a little bit of water and the corn starch. Whisk into the boiling sauce until desired consistency is reached. Season sauce to taste with salt, pepper, red wine and pickle juice.
1 Tablespoon cornstarch, salt and pepper
Serve with spätzle and roasted carrots or any sides you desire! Bread dumplings, pretzel dumplings, potato dumplings would also make great starch sides. I also love red cabbage (Rotkohl) with Rouladen!