12 wooden toothpicks coated with nonstick spray are needed. In a small bowl, mix apple, cheese, bread crumbs, thyme, lemon juice, half of the salt/half of the pepper. On a cutting board, press each chicken breast flat with one hand; using a sharp knife carefully slice each breast piece (only score the pieces, do not cut them in complete halves). Divide the apple mix into 4 portions and stuff into chicken pockets. Close the pockets with a toothpick. Sprinkle remaining salt/pepper over breasts. Dredge chicken into flour to lightly coat; tap off excess. Heat oil in a large nonstick skillet over medium-high heat. Add chicken and brown 3 mins per side. Pour 1/2 of the cider and the broth into skillet. Bring to a boil. Cover, and reduce heat to low and simmer 7 to 15 mins. or until chicken is cooked through. Remove chicken to a serving plate. Whisk mustard and remaining 1/4 cider into juices in skillet, boil mixture 3 mins. on high until reduced and slightly thickened. Spoon sauce over chicken and serve.