Preheat oven to 450F. Pat the chicken breasts dry with paper towels.

Pound the chicken breasts with the flat side of a meat hammer until about 1/8" thick.

Combine the pesto and olive oil in a bowl. Spread the pesto over the chicken breasts and add the lemon zest, garlic, salt, and black pepper.

Chop the halloumi cheese into small pieces and spread them out over the chicken.

Roll up the chicken and secure with toothpicks or butcher's twine.

Bring the remaining olive oil (for frying) to its smoking point in a cast-iron skillet.

Add the chicken to the pan and cook evenly to get a nice sear on all sides.

Place the skillet in the oven for 6–7 minutes to allow the chicken to cook through.

Once cooked and the juices run clear, remove from the oven and let rest for 5–6 minutes before serving.