Buttermilk Marinade: Place raw chicken tenders into a dish, sprinkle with salt, pepper and red pepper. (The red pepper just gives a slight pop of flavor, not spiciness.) Pour the buttermilk over the chicken, make sure to coat all the chicken. Refrigerate and marinate for minimum 1 hour and up to overnight.
Prepare Mustard Dipping Sauce: Place all ingredients into a bowl and whisk until completely combined.
Prepare Coating: Crush your cornflakes and pour into a shallow dish, similar to a pie plate. Add flour, garlic salt and pepper, stir to combine.
Place your air-fryer tray on the counter.
Starting with one chicken tender at a time wipe the sides on the edge of the bowl to remove excess buttermilk.
Roll the chicken tender into the cornflake mixture. Once coated, shake gently to remove any loose coating. Set onto air-fryer tray.
Continue with each chicken tender.
Spray the surface of your coated tenders with spray oil. (This step is a must or the coating will be dry. The oil makes sure the coating crisp up.)
Bake at 400ºF for 12 – 20 minutes, depending on how thick your chicken tenders are, or until chicken is cooked to 165 º F and coating is golden brown. Flip chicken tenders over after 6 minutes.