Preheat your oven to 400°F.
In a shallow bowl, place the arrowroot flour. In another shallow dish, beat the egg. In a third shallow dish, combine the panko breadcrumbs and grated Parmesan cheese (if using).
Take a chicken tender and dredge it in the flour, shaking off any excess.
Dip it into the beaten egg wash, ensuring it's well coated.
Finally, press it into the panko breadcrumb mixture, making sure the chicken is evenly coated. Press the breadcrumbs onto the piece of chicken to help them adhere.
Line a baking dish with parchment paper and place the breaded chicken tenders on the prepared baking sheet. Spray avocado oil spray on top of the chicken to coat tenders.
Bake the chicken in the preheated oven for about 25 minutes, flipping half way through, or until the internal temperature reaches 165°F (74°C) and the chicken is golden brown and crispy. If using air fryer, air fry at 375 degrees for 10 minutes.
Remove the panko chicken from the oven and let it rest for a few minutes before serving.