The blend of fiery mustard and jalapeño with sweet candied kumquats is what makes this sauce so sensational. The kumquats have a thin, edible rind loaded with powerful phytonutrients.
More Incredible Duck Recipes
1/2 cup dry white wine
1 tablespoon plus 1 teaspoon pure olive oil
1 1/2 teaspoons grainy mustard
1 teaspoon chopped rosemary
Four 1/2-pound duck breasts, skin and fat removed
6 ounces kumquats, sliced crosswise 1/3 inch thick
1/2 cup sugar
1/2 cup water
Salt and freshly ground pepper
2 medium shallots, thinly sliced
1 jalapeño, seeded and thinly sliced
1 tablespoon Dijon mustard
How to Make It
In a shallow dish, combine the wine with 1 teaspoon of the olive oil and 1/2 teaspoon each of the grainy mustard and rosemary. Add the duck breasts and turn to coat. Cover and refrigerate for 30 minutes.
Meanwhile, bring a medium saucepan of water to a boil. Add the kumquat slices and simmer over moderately high heat until tender, about 5 minutes. Drain the kumquat slices. In the same saucepan, combine the sugar and water and bring to a boil stirring to dissolve the sugar. Add the kumquat slices and simmer over moderate heat for 8 minutes. Transfer the kumquats along with the sugar syrup to a heatproof bowl.
In a large skillet, heat the remaining 1 tablespoon of olive oil. Remove the duck breasts from the marinade; reserve the marinade. Season the duck breasts with salt and pepper and cook over moderately high heat until browned on the bottom, about 3 minutes. Turn the duck breasts, reduce the heat to moderate and cook until browned on the bottom and medium rare, 2 to 3 minutes longer. Transfer the duck breasts to warmed plates.
Add the shallots, jalapeño and remaining 1/2 teaspoon of rosemary to the skillet and cook over moderately low heat until softened, about 4 minutes. Add the reserved duck marinade and simmer over moderately high heat until syrupy, about 3 minutes. Add the kumquats and their syrup and bring to a simmer. Blend in the Dijon mustard and remaining 1 teaspoon of grainy mustard and remove from the heat. Season with salt and pepper. Pour the kumquat sauce over the duck breasts and serve.
The candied kumquat slices can be refrigerated for up to a week.