You won't believe how easily and quickly this simple Caprese Chicken comes together. I've cooked this on my grill and grill pan with equally good results (although I'm always partial to using our kettle grill in the summer!). This chicken is very impressive for a dinner party or gathering, and doubles easily - see the recipe notes for my doubling hack if you're limited to using just a grill pan.
Prepare the chicken. Place one chicken breast onto a sheet of parchment paper. Fold the paper over the chicken. Using a rolling pin, pound the chicken breast to even thickness of a little less than 1". Set aside and repeat with the remaining chicken breasts.
Combine the italian seasoning, sea salt, garlic powder, onion powder, and pepper in a small bowl. Stir to combine.
Brush the chicken with olive oil, then sprinkle with the seasoning blend. Flip the chicken oven, then oil and season the other side.
Heat a grill or grill pan over high heat. Place the chicken breasts onto the grill and cook 5-6 minutes per side, or until the internal temperature reads 155°F using an instant read thermometer (the chicken will come to proper temperature in the next step).
Top each chicken breast with 2 slices fresh mozzarella. Continue grilling 3 minutes, or until the cheese is melted and the internal temperature reads 165°F.
Place the chicken breasts onto a platter or individual plates. Top each chicken breast with 2-3 slices of fresh tomatoes, then sprinkle with fresh basil and additional salt and pepper to taste. Just before serving, drizzle with aged balsamic vinegar or balsamic reduction. Serve immediately.
Do not cook the the chicken to proper temperature in Step 4 or it will be overcooked and on the dry side by the time the cheese is melted.
You may want to place a cover over the grill pan (or simply close your grill) to help the cheese melt. I use an inverted 9" x 12" cake pan as a "cover" for my grill pan. Make sure you use an oven mitt to remove it!
Always use an instant read thermometer to check for proper meat temperature, but especially for this recipe where you cannot use the pressure test due to the cheese.
To double this recipe (for a crowd) using a grill pan: grill the chicken breasts in batches to 155°F, then transfer to a baking sheet and cover with an inverted rectangular cake pan to keep the chicken warm. Once all the chicken breasts are cooked, top them with fresh mozzarella, then transfer the baking sheet into a heated 500°F oven. Bake 2-4 minutes, or until the cheese is melted and the chicken reaches 165°F.