After the mushrooms have been cleaned, trim the stem ends. Finely chop the mushrooms until they are uniform in size.

Melt the butter in a large skillet. Add the shallots, garlic, and one teaspoon salt and cook over low heat until tender and lightly browned. It should take about 4 to five minutes.

Add the minced mushrooms to the skillet, raise the heat, and cook, stirring, until the juices are nearly gone. Then, deglaze the mushrooms with the sherry-cooking wine and the Dijon mustard and stir to mix. Again, let cook until the sherry has evaporated. Add the fresh Thyme, more salt if needed, the nutmeg, and black pepper to taste.