1 cup fresh orange juice
1 Tablespoon minced shallot
4½ teaspoons white wine vinegar
1 Tablespoon white wine
1 Tablespoon brown sugar, firmly packed
2 Tablespoons plus 4 Tablespoons unsalted butter, chilled
4 strips orange zest
½ teaspoon salt
¼ teaspoon freshly ground pepper
¼ teaspoon freshly grated nutmeg
4 Tablespoons unsalted butter
4 boneless, skinless chicken breast halves
Bring orange juice, shallot, vinegar, wine and sugar to a simmer in a small saucepan over medium heat. Stir until sugar dissolves. Increase heat to high. Boil until sauce is reduced to ⅛ cup, about 15 minutes.
Remove sauce from heat and whisk in 2 tablespoons of chilled butter. Set pan over low heat and whisk in remaining 4 tablespoons butter, 1 tablespoon at a time. Remove from the heat briefly if sauce breaks down. Mix in orange zest. Season with salt, pepper and nutmeg. Set aside and keep warm.
Melt 4 tablespoons butter in a large skillet over medium heat. Add chicken and cook about 10 to 12 minutes per side. Transfer chicken to a serving plate and top with orange sauce. Serves 3 to 4.