2 cups chicken stock
2 ounces smoked ham
Leaves from 2 bunches flat-leaf parsley
3/4 cup double or heavy cream
1/2 teaspoon truffle oil
Salt and freshly ground black pepper to taste
Place the chicken stock and ham in a saucepan and bring to a boil. Remove from heat, let cool, then strain, discarding the ham. Meanwhile, bring a large kettle of salted water to a boil. Add the parsley and cook for 1 minute. Drain and immediately plunge the parsley into very cold water to cool. Drain again and pat dry. Process the parsley in a blender with 1/4 cup of water until liquefied. Strain through a fine-mesh sieve, using the back of a spoon to push as much of the puree through as possible. Discard the solids and set the puree aside. Bring the chicken stock back to a boil. Whisk in the cream, adjust the heat and simmer gently, uncovered, for 15 minutes. Remove from the heat, whisk in 4 tablespoons of the parsley puree and the truffle oil and season with salt and pepper if necessary. Before serving, reheat the sauce and use a whisk or hand-held immersion blender to froth it up. Serve with poached eggs, vegetables or fish.