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

Gravy:

• Add mushrooms and juice to pan and heat on medium high, scraping brown bits on the bottom and sides of the pan, until boiling.
• Create a slurry with the cornstarch and water. 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. Add salt and pepper to taste.