Chop 1 onion and the 2 garlic cloves into large pieces. Cut the second onion into very thin rings. Clean the carrots and cut into rings. Cut the pickled cucumbers into fine wedges.
Lay out the 6 beef roulades. Brush each generously with hot mustard and season with salt and pepper. Place 1-2 slices of bacon or Black Forest ham in the middle of each roulade. Cover with onion rings and pickled cucumbers to taste. Roll up each roulade and secure with a toothpick or roulade needle.
Heat the clarified butter or oil in a roasting pan over medium-high heat. Add the roulades with the coarsely chopped onion and garlic. Brown on all sides for about 8-10 minutes, keeping the pan uncovered. Deglaze the pan with the broth.
Add the carrot slices to the pan, then add a dash of red wine. Cover the roasting pan and place in a 180°C / 356°F fan oven for 1 hour 30 minutes to 2 hours, until the roulades are tender. Add more water during cooking if the broth reduces too much. The broth will reduce significantly, creating a rich sauce.
Serve with dumplings and red cabbage, or with spaetzle and salad.