Preheat oven to 375°F. Arrange salmon on baking sheet and season with salt and pepper. Bake until just cooked through, about 20 minutes.
Meanwhile, boil next 5 ingredients in heavy medium saucepan over high heat until mixture is reduced to generous 1/2 cup, stirring occasionally, about 12 minutes. Strain sauce into heavy small saucepan, pushing hard on solids to release as much liquid as possible. Set saucepan over very low heat and whisk in butter 1 piece at a time. Whisk in lemon juice; season sauce to taste with salt and pepper.
Transfer salmon to plates. Spoon sauce over and serve.
