Ingredients
1 teaspoon white-wine vinegar
1 tablespoon minced shallot
1/2 tablespoon butter
1 tablespoon Dijon mustard
1 teaspoon olive oil
1 boneless, skinless chicken breast half (6 to 8 ounces)
Coarse salt
Ground pepper
4 cups (about 2 1/2 ounces) baby spinach
Preparation
Season chicken with salt and pepper. In a large skillet, heat oil over medium-high heat. Add chicken; cook until browned, turning once, 8 to 10 minutes.
Add 1/4 cup water. Reduce heat to medium-low; cover, and simmer until chicken is cooked through, 4 to 6 minutes. Transfer chicken to a plate; cover to keep warm.
Make mustard sauce: Add minced shallot to same pan; cook over medium heat, stirring occasionally, until soft, about 3 minutes. Stir in mustard and vinegar; cook 1 minute. Remove from heat. Add butter; swirl pan until incorporated. Stir any accumulated chicken juices into sauce.
In a medium bowl, toss spinach with half the mustard sauce. Place chicken on a serving plate; drizzle with remaining sauce. Serve spinach on the side.
