Position a rack in the center of
the oven and preheat to 400°. In
a medium bowl, whisk together
the 1 tablespoon melted butter,
the sugar, egg white and 1 pinch
salt; fold in the walnuts. Spread
the walnut mixture in an even
layer on a rimmed baking sheet
and bake until golden-brown, 6 to
8 minutes. Using a metal spatula,
loosen the nuts from the pan and
transfer to a cutting board. Let
cool, then coarsely chop.
In a large Dutch oven, melt
the remaining 4 tablespoons
butter over medium-low heat;
add the onions and cook,
stirring occasionally, until
softened but not browned, about
10 minutes. Stir in the chicken
broth and port, cover partially and
simmer for 10 minutes. Stir in the
chestnuts and cook for 5 minutes.
Gradually whisk in the chestnut
puree and cook until heated
through, about 5 minutes more.
Using an immersion blender,
puree the soup (or mix in batches
using a standing blender). Season
with salt and pepper.
Ladle the soup into 10 bowls.
Swirl 1 tablespoon cream into
each serving. Sprinkle the parsley
and candied walnuts on top.