Preheat oven to 375. On medium-high heat, melt butter until it’s bubbly with olive oil in a heavy cast iron skillet. Season chicken thighs with a pinch of kosher salt, pepper and smoked paprika on both sides. Start cooking skin side down in and set your timer for 10 minutes. Flip over and cook for another 10 minutes. If the chicken skin looks too dark, your heat is too high, so crank it down. You want the skin to have a golden sheen to it. Flip for a third time and cook for another 10 minutes. (30 minutes total).