Use a meat mallet to gently flatten your top round beef steak slices to ¼ inch thickness. Season each slice generously with kosher salt and freshly ground black pepper, then spread a layer of yellow German mustard across the top. Top with crispy bacon strips, dill pickles, and chopped yellow onion for added flavor and crunch.

Starting with the end featuring the dill pickles, carefully roll up each beef slice tightly to encase the fillings. Secure the rolls with sturdy toothpicks to keep everything neatly in place.

In a large Dutch oven, combine unsalted butter and olive oil and heat over medium-high heat until the butter has melted and begins to bubble. Add your beef rouladen to the pot and brown them on all sides, approximately 3-4 minutes per side.

In the same pot with the flavorful drippings, add chopped yellow onion, carrot, and celery. Sauté the mixture for about 5-7 minutes until tender and aromatic, then stir in minced garlic and cook for an additional minute.

Pour in soy sauce, low-sodium beef broth, and tomato paste, stirring to combine thoroughly. Return the browned rouladen to the pot, cover, and let simmer on low heat for 1½ to 2 hours until fork-tender.

Once tender, carefully remove the rouladen and set aside. Strain the broth and vegetables through a fine-mesh sieve and return to the pot. Mix cornstarch with water to create a slurry, whisk into the broth until thickened.

Arrange the beef rouladen on a serving platter and generously pour the rich gravy over the top. Garnish with freshly chopped parsley.