Peel the onions; cut one into 8 wedges and finely chop the other. Wash the carrot and celery; cut each into 4 sticks. Finely chop the pickled cucumbers. Season the beef roulades with salt and pepper. Brush each with mustard and top with a bacon slice. Distribute the chopped pickles, carrot sticks, celery sticks, and one onion wedge on each roulade. Roll up tightly and secure with toothpicks or roulade needles.
Heat the oil in a roasting pan over medium-high heat. Brown the roulades on all sides, about 8 minutes. Add the finely chopped onion to the pan and fry together for 2 minutes.
Wash the soup vegetables and cut into small pieces. Add to the pan. Stir in the tomato paste and cook for 1–2 minutes. Pour in the red wine and simmer for about 5 minutes until reduced by about half. Pour in the meat stock. Add the bay leaves, thyme sprig, and sage leaves. Cover the roasting pan.
Place the covered roasting pan in a preheated oven at 180°C (350°F). Braise on the middle rack for 1.5 hours.
Remove the roulades from the stock and set aside. Remove and discard the bay leaves, thyme, and sage. Puree the remaining sauce with an immersion blender until smooth. Season to taste with salt and pepper. Serve the roulades with the sauce.