Sauce Albert (Béchamel, Shallots, Horseradish, Mustard, Sherry, Vinegar)

This 2nd generation mother sauce derives from a finished Sauce Béchamel. Serve with light roasted meats.

Sauce Béchamel:
4 Tbsp. butter
4 Tbsp. all-purpose flour, unbleached
2½ cups milk, warmed but not hot
pinch nutmeg, freshly ground
¼ tsp. sea salt
⅛ tsp. white pepper, freshly ground

Sauce Albert:
2 shallots, minced or finely diced
2 Tbsp. horseradish, freshly grated
½ tsp. dry mustard
1 Tbsp. sherry
1 Tbsp. vinegar
1-2 Tbsp. butter

Make the Béchamel Sauce:
Melt the butter in a heavy-bottomed saucepan, add the shallots, horseradish and mustard. Cook for 2 minutes. Stir in the flour and cook, whisking constantly, until the flour is fully aborbed and cooked, about 2 minutes.

Add the sherry, vinegar and warm milk gradually, continuing to whisk as the sauce thickens. Bring it to a boil. Add nutmeg, salt and pepper, lower the heat to simmer, and cook, stirring for 2-3 minutes more. Remove from the heat, add a chunk of butter and stir until melted.

Serve immediately.

Makes about 2 cups.