• Preheat oven to 350˚F.
• In a Dutch oven or skillet on medium low, melt 2 Tablespoons butter and cook onions, until soft and slightly browned, about 5-6 minutes. Remove from heat.
• Lay beef rouladen out on work surface (cover the workspace with plastic wrap for easy cleanup).
• Spread mustard over each beef rouladen piece. Top each with a slice of bacon and fried onions. Season with pepper.
• Add a pickle to one end of each rouladen and roll up tightly. Secure with toothpicks.
• In a Dutch oven or skillet on medium heat, melt butter and brown rouladen on all sides in two batches. Add all browned rouladen to Dutch oven or a roasting pan. Add pickle juice* and enough beef broth to cover rouladen about two thirds of the way up. Add pickles and carrots if desired.
• Cover** and roast 1 hour and 45 minutes to 2 hours, until beef is fork tender, turning rouladen over after 1 hour if desired.
• Remove rouladen (and pickles and carrots if using) from pan and cover until gravy is ready. Remove toothpicks before serving. Serve with elbow macaroni, rice, or mashed potatoes along with the vegetables and gravy.

Gravy

• To the same pan on medium high, add mushrooms to the rouladen juices, scraping brown bits on the bottom and sides of the pan, until boiling.
• In a small bowl, combine cornstarch and water to make a slurry.
• While whisking the juices in the pan, slowly add the slurry until the gravy reaches desired consistency. Add additional beef broth and pickle juice as desired to make extra gravy. Season with salt and pepper to taste.