Throw the mozzarella in the freezer before you start, so that it will be a little easier to slice.
Trim chicken, and season it with sea salt and pepper. Heat the olive oil in a 12″ cast iron skillet over medium-high heat for one minute.
Add the chicken thighs to the skillet and cook them over medium-high heat for 6-7 minutes a side, or until browned and cooked through. Remove chicken to a separate plate.
While the thighs are cooking, slice your zucchini and tomatoes. Dice the onion and mince garlic (if using cloves).
After removing the chicken, reduce heat to medium under the same skillet. Add the onion to the pan and saute for two minutes, scraping up the browned bits from the bottom of the skillet.
Stir in the garlic and saute just briefly, then add in the zucchini. Season with basil, oregano, and crushed red pepper, then cook over medium heat for 7 minutes, stirring and flipping over the zucchini occasionally. Stir in the tomatoes and cook for another 4 minutes, stirring occasionally.
While the veggies are sauteing, pull mozzarella out of the freezer and slice.
Once the veggies are cooked, turn off the heat under the pan. Top the sauteed veggies with cooked chicken. Drizzle everything with balsamic vinegar, then top with sliced mozzarella and sprinkle with shredded Parmesan.
Move the entire skillet to the oven and broil for 8 minutes to brown the cheese. Serve hot.
I topped my Caprese skillet with chopped fresh parsley for a little contrast in the photos, but that’s totally optional.
Caprese Chicken and Zucchini Skillet from Mashup Mom: https://www.mashupmom.com/caprese-chicken-and-zucchini-skillet/