To begin, prepare the beef slices by seasoning both sides with salt and pepper. Lay the slices flat on a clean work surface. Spread 1 tablespoon of Dijon mustard evenly over each slice. This layer adds flavour and helps the filling adhere to the beef.

Layer 2 slices of bacon lengthwise on top of each beef slice. Add a few onion slices and one pickle quarter to each. Roll the beef tightly from the shorter end, encasing the filling. Secure each roll with kitchen twine or toothpicks to maintain its shape during cooking.

Heat a large skillet over medium-high heat and add a drizzle of oil. Sear the beef rolls on all sides until browned, about 2–3 minutes per side. This step locks in the juices and builds flavour. Transfer the rolls to a plate and set aside.

In the same skillet, melt the butter over medium heat. Add the remaining onions and sauté until golden and softened. Stir in the flour and cook for 1–2 minutes to form a roux, which will thicken the sauce.

Gradually add the beef broth and red wine, whisking constantly to avoid lumps. Add the tomato paste and bay leaf. Bring the sauce to a simmer, allowing the flavours to meld for 5 minutes. Adjust seasoning with salt and pepper.

Preheat your oven to 160°C (320°F). Return the seared beef rolls to the skillet, ensuring they are submerged in the sauce. Cover with a lid or foil and transfer the skillet to the oven. Braise for 1.5–2 hours, or until the beef is tender and easily pierced with a fork.

Once cooked, carefully remove the beef rolls and set them aside on a serving platter. Strain the sauce into a saucepan, discarding the bay leaf. Simmer the sauce on the stovetop for 5–10 minutes to thicken further if needed. Adjust the seasoning as desired.

Serve the Rouladen hot, paired with creamy mashed potatoes or spätzle, and a side of red cabbage or steamed vegetables. Drizzle the sauce generously over the beef rolls. For a classic presentation, garnish with freshly chopped parsley and offer extra sauce at the table for dipping. Complement the meal with a glass of dry red wine for an authentic German dining experience.