Mustard sauce with vermouth and thyme

From Cook's Illustrated

The Dijon mustard lends a creaminess to this sauce, while the whole-grain mustard adds texture and visual appeal.

Ingredients

1 1/2	cups chicken stock or canned low-sodium chicken broth
2	tablespoons cornstarch
2	tablespoons unsalted butter
3	medium shallots , chopped fine
2	cups dry vermouth
1	tablespoon brown sugar
1/2	cup Dijon mustard
1/4	cup whole grain mustard
1	tablespoon chopped fresh thyme leaves
	Table salt and ground black pepper

Instructions

Whisk together chicken stock and cornstarch; set aside. Heat butter in 12-inch skillet over medium heat until foaming; add shallots and sauté until softened, about 3 minutes. Stir in vermouth and sugar; increase heat to medium-high and simmer until alcohol vapors have cooked off, about 4 minutes. Whisk chicken stock and cornstarch mixture to recombine, then gradually whisk into simmering liquid; return sauce to simmer until thickened, stirring occasionally. Off heat, whisk in Dijon and whole-grain mustards and thyme; season to taste with salt and pepper. (Can be cooled to room temperature and refrigerated up to 2 days. Reheat in medium saucepan over medium-low heat.) Serve with ham.