Prepare filling as follows: Heat 1 tbs of olive oil in a large deep skillet over high heat. Add all ingredients, except the feta cheese. Cook, stirring constantly until spinach has wilted; remove to a bowl and stir in the feta cheese. Keep it warm.

Butterfly chicken breasts, but do not cut all the way through. Sprinkle chicken with salt & pepper if desired.

Heat 2 tbs olive oil in the same skillet over medium-high heat. Add chicken to the pan and brown well on each side—about 8 minutes per side.

Remove chicken and place 1/4 of the spinach mixture in each chicken breast. Return to the skillet, cover and cook over medium-low heat for about 10 minutes or until chicken reaches 165 degrees F on a thermometer or the juices run clear.