In a medium-sized bowl, add the flour, baking powder, cayenne, garlic powder, salt, and pepper, whisk to combine, set aside.
In a medium-sized bowl, whisk together the buttermilk and the egg until combined, set aside.
Start heating up your oil to 325°F. I like to use a dutch oven for this. You can also use a deep fryer or a large skillet with deep sides. You need about 3 inches of oil up the side of the pan. Make sure you do not overfill the skillet if you are using it, when adding the tenders the oil will rise.
While the oil heats, bread the tenders. Do this one tender at a time.
Place tender into the flour mixture. Shake off any excess.
Place it into the buttermilk mixture and coat the tender well, let any excess drip off.
Place it back into the flour mixture, coat the tender in the flour and pat down the flour on the tender so it sticks well and forms a crust. Shake off any excess flour.
Next, place the tenders very carefully into the hot oil. Fry for about 3-5 minutes per side, or until the internal temperature reaches 165°F. Place the tenders on a wire rack above a sheet tray while you fry the remaining tenders.
Add the butter into a small saucepan over medium-low heat. Let the butter melt then add the brown sugar, cayenne, garlic powder, onion powder, and salt.
Whisk to combine and continue to whisk until the sugar dissolves and the sauce comes together for about 2 minutes.
Brush the tenders with the sauce and serve.