Spinach & Blue Cheese Stuffed Chicken

I found this recipe on Cooking Light, but adapted it a little at the end by adding sour cream. It was very good. The blue cheese was very mild, I might add a little more next time.

Spinach & Blue Cheese-Stuffed Chicken Breasts

1 teaspoon vegetable oil, divided
1 1/4 cups finely chopped onion, divided
4 garlic cloves, minced
1/2 cup frozen chopped spinach, thawed, drained, and squeezed dry 2 tablespoons crumbled blue cheese 1 teaspoon Dijon mustard
4 (4-ounce) skinned, boned chicken breast halves 1/4 teaspoon pepper 1/3 cup dry white wine
1/2 teaspoon dried thyme
1 cup low-salt chicken broth
2 tablespoons Dijon mustard
1/4 cup sour cream

Heat 1/2 teaspoon oil in a large nonstick skillet over medium heat. Add 1/4 cup onion; sauté 6 minutes or until tender. Add garlic, and sauté 1 minute. Add spinach, and sauté 3 minutes. Combine spinach mixture, cheese and 1 teaspoon mustard in a small bowl. Stir well; set aside. Wipe pan dry with a paper towel.

Cut a horizontal slit through thickest portion of each chicken breast half to form a pocket. Stuff about 2 tablespoons spinach mixture into each pocket. Sprinkle chicken with pepper.

Heat 1/2 teaspoon oil in skillet over medium-high heat. Add chicken; sauté 6 minutes on each side or until chicken is done. Remove chicken from skillet. Set aside, and keep warm. Add 1 cup onion to pan, and sauté 5 minutes. Add wine and thyme; cook 3 minutes or until reduced by half. Add broth and 2 tablespoons mustard; cook 4 minutes or until slightly thick, add 1/4 cup of sour cream, stirring occasionally. Return chicken to skillet; cover and simmer 2 minutes or until thoroughly heated. Serve sauce with chicken.

Source: Adapted from Cooking Light