Aside from being a super healthy Mediterranean meal, it's fast, simple and can be made ahead. You can make the whole thing the day before, chill it and then just reheat it on the stove top when you're ready to eat.
Technique Tip: Don't waste what's left in your canned tomato can. Use the container to measure the water and swish the water around to get out all of the tomato goodness!
Swap Option: If you're not a fan of dark meat chicken, you can use boneless skinless chicken breasts.
Preheat oven to 375°F.2.
Heat a large cast-iron pan or oven proof skillet over high heat. Liberally season the chicken with salt and pepper. Once the pan is hot, add enough olive oil to coat the bottom of the pan. Add the chicken thighs, skin side down, and sear until the skin starts to brown, about 5 minutes. Flip the chicken and sear for a few minutes more and then remove the chicken to a plate.3.
Add the rest of the olive oil to the pan. Add the onion and garlic and cook until onions start to soften. Add the diced tomatoes. Add a few tablespoons of water to the empty tomato can and swirl to get the rest of the tomato out and add to the pan. Then add the pepperoncini (plus the liquid), olives and capers. Stir to combine and bring to a bubble.4.
Add the chicken thighs back into the pan, skin side up, and bring the mixture to a bubble. Once boiling, place the lid on top of the pan. Transfer to the oven and bake for 30 minutes. Remove the pan from the oven and remove the lid. Turn the oven on broil. Place the pan back into the oven and broil until chicken browns on top, about 5 minutes.5.
Remove from the oven and let cool for a few minutes before serving.