Do not rinse the leg of veal; pat it dry, trim off the thin outer membrane, and if bloody, blot dry with paper towel.
Pound lightly with a meat mallet, then lard with bacon strips using a larding needle.
Season with salt, and tie with kitchen string so it keeps its shape nicely while cooking.
Line the bottom of a large pot with butter and bacon slices, scatter over the diced carrot and parsley root, and lay the meat on top.
Pour in enough meat stock or water to just cover the vegetables, cover and simmer over low heat for about 1.5-2 hours, until the meat is tender, topping up with water if needed.
Half an hour before serving, lift the meat into a roasting pan, brush with butter and a spoonful of sour cream, and place in a 200°C oven for 20-25 minutes to take on a light golden colour.
Stir half a tablespoon of flour into the remaining braising liquid with the vegetables, bring to a boil, then push through a sieve.
If the sauce is too thick, thin with a little stock, stir in the sour cream, the lemon juice and a pinch of grated zest, and bring to a boil once more.
Remove the string, slice the meat, arrange on a platter, and serve drizzled with the sauce.
Based on: Malatinszky Fanny szakácskönyve (a classic Hungarian cookbook), modernised. Calories and protein are estimated.