One day in advance, combine the wine, shallots, leeks, garlic, bouquet garni and salt in the All-Clad 5 Qt. Dutch Oven. Bring the contents to a rapid simmer and cook until you are no longer able to smell the aroma of alcohol. Cool the liquid completely then add the veal to the pot. Add enough cold water to barely cover the veal and stir well. Cover the pot and refrigerate it overnight to allow the meat to marinate.
The next day, place the Dutch Oven on the stove and slowly bring it to a simmer. Skim and discard any impurities that rise to the surface and cook for 5 minutes. Use a slotted spoon to remove the veal from the pot and transfer it to a large plate for the time being. Remove and discard the shallots, leeks and garlic. Bring the liquid to a rapid boil and cook until most of the liquid has evaporated. Take care not to allow any caramelization to occur. While the liquid is reducing, mix the softened butter with the flour to form a thick paste. Once the liquid has reduced, add the chicken stock. Bring the stock to a very low simmer then whisk in the butter and flour paste until it is completely dissolved and lump free. When the liquid begins to thicken, return the veal, season with the white pepper and cover with the lid. Cook for 30 minutes at the lowest simmer possible. Add the cream, pearl onions, carrots and mushrooms; cover and cook for an additional 30 minutes. Test to see that the veal is very tender but not falling apart by piercing it with a paring knife, also test the carrots and onions. Cook longer if necessary. When all is tender, turn off the heat and gently stir in the crème fraiche. Adjust the seasoning with salt and a couple drops of lemon juice if necessary. Add the chopped truffles, if you are using them, at this time. Cover the Dutch oven and allow it to rest off of the heat for 15 minutes before serving. To serve, spoon the blanquette over a base of rice pilaf or buttered egg noodles such as “pappardelle”. Sprinkle with finely minced chives and shave additional truffles over the top if desired.