Gather all ingredients before starting the recipe.
Melt 1 tbsp unsalted butter in a medium sized sauce pan over medium heat.
Add 1 whole shallot, chopped and sauté covered until the shallots are softened.
Add 1/3 cup dry white wine and reduce for one minute.
Add 1 1/2 tbsp Dijon mustard, whisk to combine. Add a squeeze from 1/2 of a lemon, season with kosher salt and freshly ground black pepper.
Add 3/4 cup heavy cream and cook, while stirring continuously, until the cream thickens, about 5 minutes.
