Preheat oven to 425℉ or 225℃. Pat the chicken thighs dry with a paper towel. Season both sides of the chicken liberally with kosher salt and black pepper.
To a COLD cast iron skillet, add the chicken thighs, skin down. You do not need to add oil to the pan. Turn the heat to medium high heat and cook for 6-8 minutes, or until the skin is golden brown.
Remove the chicken thighs from the pan and add carrots and shallots to the pan, tossing them to coat in the rendered fat from the chicken. If there's not enough to coat them well, you can add a teaspoon of olive oil. Season the carrots and shallots with about 1/2 teaspoon kosher salt. Nestle the chicken thighs, skin side up, back into the cast iron pan.
Roast the chicken thighs at 425℉/220℃ for 20 minutes, or until they register 165F for an internal temperature and the carrots have softened. Stir in butter or olive oil to coat all the veggies. Taste and adjust any seasonings.
Notes
Carrots can be substituted with most root vegetables like parsnips, beets, turnips, radish - whatever you like. You can also just make the chicken thighs plain, but it's nice to have a built in side dish.
These chicken thighs pair perfectly with this tahini sauce! So good on the carrots too.
Use a meat thermometer to check the internal temperature of the chicken once it is finished roasting in the oven. It needs to be 165 degrees Fahrenheit.