Trim any visible fat from the chicken and season with black pepper.
In a large bowl, combine the chicken with ½ cup of the hot sauce, tossing or stirring to coat. Cover and marinate, in the fridge, for at least one hour.
Preheat oven to 400° Arrange chicken on a baking tray lined with parchment paper.
Bake 20 minutes, flipping halfway through. The chicken will be golden brown.
While the chicken cooks make the spicy buffalo sauce. In a microwave safe small bowl, heat the remainder of the hot sauce for 1-2 minutes. Or use a small saucepan over medium-high heat. Add the butter, stirring until combined.
Using tongs, submerge each piece of chicken in the buffalo sauce until coated. Return the chicken to the baking sheet.
Frank's Red Hot is a medium hot sauce. If you love buffalo chicken but want less spice, try a mild buffalo sauce.
Be sure to heat the hot sauce before adding the butter. If you melt the butter and then add it to the hot sauce, the butter will solidify again.
Chicken should be cooked to an internal temperature of 165°. Use a meat thermometer to measure the temperature.
Leftover buffalo chicken thighs should be stored in the fridge in an airtight container for up to 3 days. To reheat, preheat oven or air fryer to 400°. Arrange the chicken in a single layer on a baking sheet or air fryer basket. Heat for 10 minutes in the oven, or 5 minutes in the air fryer.