In a large skillet, fry the chopped bacon with minced carrots until the bacon is fully cooked. Drain most of the fat, reserving about 1-2 tablespoons in the pan for later use.

In a mixing bowl, combine the cooked bacon and carrots with minced onion, minced dill pickle, yellow mustard, and rye seeds (if using).

Lay one thin slice of beef flat and spread about a teaspoon of the filling mixture across it, leaving about 1/4 inch of space around the edges.

Starting from one of the narrow ends, roll the beef up tightly and secure with a toothpick. Repeat with remaining beef slices.

Heat the reserved bacon grease in the skillet and brown the beef rolls on all sides until they develop a nice crust.

Add water to the pan, cover, and simmer on low heat for 1 hour until the beef is fork-tender.

Remove the rouladen from the pan and keep warm.

Mix flour (or cornstarch) with 1/2 cup of the cooking liquid until smooth, then pour this mixture back into the boiling pan juices, stirring constantly until it thickens to your desired consistency.

Return the beef rolls to the gravy for about 5 minutes, gently rolling them to coat evenly.

Season with salt and pepper to taste before serving.