This is the filling which goes between the slices of beef in Beef Wellington, following the recipe in Julia Child’s Mastering the Art of French Cooking. This is enough for stuffing a 2-1/2 lb. beef tenderloin. The photo shows the raw beef slices with the duxelles stuffing.
1 lbs. mushrooms, cleaned and finely chopped
3 Tbs. butter
¼ cup shallots, finely chopped
1/3 cup mild ham, finely chopped
1-1/2 Tbs. flour
1/3 cup dry Madeira (Sercial) or Sherry (Fino)
1/3 cup liver paste (such as braunschweiger)
1 egg yolk
½ tsp. dried tarragon
Salt and pepper to taste
Before starting to cook, be sure that the mushrooms, shallots, and ham and finely chopped.
Heat the butter over medium heat in a large frying pan until bubbling. Add the mushrooms, and saute until they have released all their liquid and have begun to brown. Add the shallots and ham, and cook until the shallots are translucent. Add the flour and cook for about 2 minutes. Deglaze the pan with the Madeira or sherry. Remove from the heat and mix in the liver paste, egg yolk, tarragon, and salt and pepper. Set aside for use in Beef Wellington.