Slice a few of the chanterelles and cook them in the butter for 5 minutes. Skim the slices from the pan and reserve for garnishing the stew. Add the parsley stems, scallions, garlic, snails and the remaining chanterelles to the butter and cook for 5 minutes. Add the flour and stir until the flour looks gritty. Slowly add the chicken stock, wine, herbs and spices, season to taste, and simmer for 2 hours. Beat the egg yolks, vinegar and cream together and stir in a little of the simmering liquid. Turn the heat to the lowest point and add the egg yolk mixture to the stew. Stir until creamy and silken. Serve in shallow bowls, garnished with the chanterelle slices.