Preparation Preheat oven to 450°F. Stir 2 tablespoons mustard and 1 tablespoon melted butter in small dish. Oil small rimmed baking sheet and place salmon on sheet, skin side down. Sprinkle salmon with salt. Spread top of salmon with mustard mixture and season generously with pepper. Bake until salmon is cooked through and mustard browns, about 10 minutes. Meanwhile, heat remaining 1 tablespoon butter in heavy small skillet over medium heat. Add shallots and sauté 2 minutes. Add preserves and vinegar; stir until preserves melt and mixture is smooth. Bring to simmer. Season sauce to taste with salt and pepper. Spoon sauce over fish and serve.
Preparation Preheat oven to 450°F. Stir 2 tablespoons mustard and 1 tablespoon melted butter in small dish. Oil small rimmed baking sheet and place salmon on sheet, skin side down. Sprinkle salmon with salt. Spread top of salmon with mustard mixture and season generously with pepper. Bake until salmon is cooked through and mustard browns, about 10 minutes. Meanwhile, heat remaining 1 tablespoon butter in heavy small skillet over medium heat. Add shallots and sauté 2 minutes. Add preserves and vinegar; stir until preserves melt and mixture is smooth. Bring to simmer. Season sauce to taste with salt and pepper. Spoon sauce over fish and serve.