Chicken a la King

Yield: Two large, or four small portions.

6 tablespoon unsalted butter
1/2 pound sliced mushrooms
2 large shallots, minced
1 cup diced sweet bell peppers
salt and freshly ground black pepper to taste
1/3 cup to 1/2 cup all-purpose flour, depending on how thick you want it
1/4 cup dry sherry (there is no substitute, except maybe a little splash of a mild, sweeter vinegar)
3-1/2 cups chicken stock or broth
pinch of freshly grated nutmeg
pinch of cayenne pepper
2 teaspoons fresh thyme
1 tablespoon Italian parsley
1/3 cup creme fraiche or heavy cream
4 cups cubed roasted chicken
fresh chives to garnish