3tablespoonsflour whisked into additional 1/2 cup cool beef broth
Rub the roast down with salt and freshly ground black pepper. Generously rub it down with German mustard.
Heat the oil in a Dutch oven over high heat. Once hot, add the roast and generously brown on all sides. This will give the roast its wonderful flavor.
Add the onions and the butter and cook for a couple of minutes. Add the garlic and cook for another minute. Add the white wine and boil for 3 minutes until mostly evaporated.
Add the bay leaf, thyme, beef broth and carrots (they will add a touch of sweetness to the gravy). Bring it to a boil, reduce the heat to low, cover and simmer for about 90 minutes or until the roast is nice and tender. (Alternatively roast it in the oven for about 3 hours if using a marbled cut like pork butt and for about 2 hours if using pork loin or pork shoulder. Check periodically for doneness - as soon as the roast is tender - to avoid overcooking.)
Discard the carrots and bay leaf. Transfer to the roast to a warmed platter and tent with foil to keep warm. Whisk in the flour slurry and simmer until thickened. Add a couple of teaspoons or so of mustard and salt and pepper to taste.
Slice the roast and serve with the gravy, potatoes and German sauerkraut.