Wash and cut carrots into rondelles (rounds). Put them in a pot with cubed potatoes (you can leave on the skins if the potatoes are young and organic) and a diced onion. Add a bay leaf for flavor, cover with chicken broth, and simmer gently until tender. Remove the bay leaf and purée with an immersion blender. If the resulting ensemble is too thick, add more liquid (either broth or water). Add a generous grating of truffle and stir to blend flavors. Serve hot, adding about a teaspoon of cream to the center of each dish. With a knife, make a pinwheel design on the top of each bowl of soup, and finish off with a fresh grating of truffle and a sprig of chervil.