2 cloves garlic, peeled and chopped
1 shallot (2 oz.), peeled and chopped (1/3 C.)
1 C. dry vermouth
1/2 C. fat-skimmed chicken broth or fish stock
1 C. whipping cream
1/3 C. chopped pitted picholine olives (or other mild green olives; see notes)
2 tsp. chopped fresh thyme leaves
Salt and fresh-ground pepper
1 boned salmon fillet (3 lb.), skinned
1 T. butter, cut into small pieces
1/2 C. dry white wine
1 T. chopped fresh tarragon
Fresh thyme sprigs, rinsed

In a 6- to 8-inch frying pan over high heat, boil garlic and shallot in vermouth until mixture is reduced by about half, 5 to 8 minutes. Add broth and bring to a boil again. Add cream, olives, and chopped thyme. Boil, stirring occasionally, until sauce is thick enough to coat the back of a spoon and is reduced to about 1 1/4 C., about 5 minutes. Add salt and pepper to taste. Cover and set aside. Rinse salmon fillet and pat dry. With tweezers, pull out pin bones. Lay fillet in a buttered 12- by 17-inch baking pan. Dot the fillet with butter, drizzle with wine, and sprinkle with tarragon. Sprinkle lightly with salt and pepper. Bake in a 400° oven until salmon is barely opaque but still moist-looking in center of thickest part (cut to test), 13 to 18 minutes. Slide salmon onto a platter. If sauce is cool, stir over medium-high heat until hot. Drizzle fish with some of the sauce; serve remaining to add to taste. Garnish fish with thyme sprigs.