Add 1/2 cup beef broth, 1/2 cup water, 2 tablespoons heavy cream, 1 teaspoon Dijon mustard, 1/2 teaspoon Worcestershire sauce, 1/4 teaspoon dried thyme, and 1/4 teaspoon black pepper. Scrape up any browned bits from the bottom of the pan with a wooden spoon. Simmer until the sauce is reduced and thickened slightly, 4 to 6 minutes.