Peel the garlic cloves and cut into sticks. Clean the soup vegetables and roughly dice if necessary. Peel and quarter the shallots. Mix the mustard and turnip tops together.
Preheat the oven to 200 ° C top and bottom heat.
Wash the meat and pat dry. Pierce the roast all around with a sharp knife and press a piece of garlic into each puncture. Then rub it thoroughly with coarse salt and freshly ground black pepper.
Heat the frying fat in a pan and let the meat take color on all sides. Then place in a roasting pan, brush with the beet and mustard mixture and set aside.
In the same pan, sauté the soup vegetables and shallots. When frying add 1-2 strong pinches of sugar and fry until the sugar caramelises (gives the sauce a nice color afterwards). Deglaze with the stock or stock, bring to the boil briefly and add to the meat.
Put the roast in the oven and reduce the heat to 150 ° C after 20 minutes. Pour in a little more water every 20-30 minutes. The roast should stay in the oven for approx. 90 to 120 minutes, depending on its size.
If you are not sure: If clear meat juice comes out when piercing, the roast is done.
As soon as the roast is done, take the roasting pan out of the oven, wrap the roast in aluminum foil and let it rest for approx. 10 minutes.
Put the vegetables from the roasting pan in a saucepan, add a little water if necessary. Add the sour cream and stir everything until smooth with a hand mixer.
Slice the roast and serve with the sauce.
This goes well with potato dumplings, ribbon noodles and steamed vegetables of your choice (I prefer green beans with a little herb butter and garlic).