Brown diced bacon in large skillet. Use small amount of butter if needed. Once bacon is crisp, remove from skillet.
Score the sausages with a knife (cut 2-3 shallow slits into two sides of each sausage). Place the sausages in the skillet and brown them in the bacon grease. Once browned, remove and set to the side.
**If you like the vinegar flavor of the kraut, no need to rinse, but if you like a milder flavor, rinse the kraut in cold water.** Add sauerkraut to the skillet (there may be a small amount of bacon grease still in the skillet; if there is more than a teaspoon or so, remove excess). Add the onion soup mix, the broth and the bacon; add salt and pepper to taste. Toss together. Cover and cook on medium heat for about 5-10 minutes to heat through, stirring occasionally.
Add sausages to the top of the kraut. Lower heat. Cook on low for about 20 minutes.
Just before kraut is done, butter the insides of the rolls and broil in oven until toasted. Put mustard, a sausage and kraut into each bun and enjoy!