Preheat oven (electric cooker: 175 °C/circulating air: 150 °C/gas: level 2). Peel, wash and roughly chop the carrots and potatoes. Cook in 1⁄2 l water with 1 teaspoon broth for about 20 minutes.
Dab the fillet dry, cut it into 8 medallions and tie them into shape if necessary. Wash the rosemary and put something aside for garnishing. Peel onion and garlic and dice finely.
Heat the oil. Add rosemary. Fry the medallions for 3-4 minutes on each side, season and place on a baking tray. Cook in a hot oven for about 10 minutes.
Briefly fry the onion and garlic in hot frying fat. Sauté the tomato paste and 2 teaspoons of sugar in it. Deglaze with 400 ml water and vinegar. Stir in 1 teaspoon broth. Let simmer for about 5 minutes. Thicken the sauce and season to taste.
Drain the carrots and potatoes, except for about 100 ml of water. Add butter and mash finely. Season to taste with salt and garnish with the rest of the rosemary.