In an 8- to 10-inch frying pan over medium-high heat, stir or shake 1 tablespoon slivered almonds until golden, about 3 minutes. Pour from pan. Add 1/2 cup minced shallots or onion and 1 tablespoon butter or margarine. Stir over high heat until shallots are limp, about 2 minutes. Add 1 tablespoon all-purpose flour to pan and stir until mixture is lightly browned, 2 to 3 minutes. Add 1 cup dry sherry, 1 cup fat-skimmed chicken broth, and 1/4 teaspoon dried thyme. Boil, stirring often, until sauce is reduced to 1 cup, about 7 minutes. Finely chop almonds and stir into sauce.
If making sauce up to 1 day ahead, cover and chill.