• Working with one at a time, place a chicken breast into a re-sealable bag. Don't zip it up all of the way so air will be able to escape.
• Using the flat side of a meat tenderizer, pound the chicken breast to about a 1/2-inch thickness. Repeat with remaining chicken breasts.
• Next whisk the mustard, salt, paprika, cayenne and red pepper flakes, honey, garlic and lemon juice in a small bowl. Reserve 1/4 cup of the honey mustard mixture to use later on.
• Place the chicken breasts into a large bowl, pour the remaining honey mustard mixture over top. Toss and cover the bowl with plastic wrap and let it sit for about 30 minutes at room temp.
• Preheat the grill on medium- medium high heat, grill chicken for about 6 to 8 minutes per side or until chicken is done.
• Transfer the grilled chicken to a platter to rest for 5 minutes. Pour the reserved 4 tablespoons of honey-mustard sauce over chicken before serving.

TO BAKE IN THE OVEN:

• Preheat your oven to 350° and lightly grease a baking dish.
• In a medium bowl whisk together the mustard, salt, paprika, cayenne, pepper flakes, honey, garlic and lemon juice. Reserve 1/4 cup of the honey mustard mixture to use later on.
• Toss chicken in the remaining sauce to coat and place in your prepared dish.
• Bake for 30 minutes, then turn chicken over and bake another 10 minutes or until cooked through.
• Lastly, drizzle with desired amount of the remaining sauce before serving.