Heat the larger of the two cast-iron skillets over medium-low heat, and preheat the oven to 425F.
Remove the chicken thighs from their packaging and season all over (including under the skin) with salt and pepper.
Sprinkle a layer of potato starch onto a plate, and dip the skin side of each chicken thigh into the starch to form a thin coating.
Place the chicken thighs into the heated cast-iron pan, skin-side down. Lay a piece of parchment paper over the thighs, and place a second cast-iron pan on top of the parchment paper to weigh the thighs down.
Transfer the thighs, while still sandwiched between the cast-iron pans, into the preheated oven and bake for 35 minutes.
Meanwhile, make the buffalo sauce by melting the butter and hot sauce together. Set aside.
Remove the chicken thighs from the pan. At this point, the chicken skin should be nice and crispy. Toss with the buffalo sauce to coat.