Rinse the chicken breasts under cool water and pat dry with paper towels. Pound the thick side of the breasts to even out the thickness. You can use a meat mallet if you have one. If not, just pound the breast lightly with the bottom of a heavy skillet.

Mix the salt, pepper, garlic powder and paprika together in a small bowl and set aside.

Brush one side of the chicken breasts with oil, sprinkle half the spice mixture over the breasts then flip them over and repeat. Transfer the seasoned breasts to a gallon-sized plastic bag or shallow baking dish and cover with plastic wrap. Refrigerate for at least 30 minutes or overnight.

When you’re ready to cook the chicken, preheat the grill to medium-low. Remove as much of the black char off of the grates as possible. Once it’s hot, brush the grates with a little oil.

Place the chicken breasts on the grill, smooth side down and grill 3–4 minutes until the chicken becomes golden brown and achieves those beautiful grill marks.

Flip the breasts and immediately place 2 slices of mozzarella on each. Place the tomato slices on the grill to heat and cook 3–4 minutes with the lid closed. Open the cover, remove the tomatoes from the grill then lay them on top of the chicken breasts—the mozzarella should be melted at this point.

Continue cooking just until the thickest part of the breast feels firm to the touch or registers 165 degrees on a meat thermometer.

Remove the chicken from the grill, place on a serving platter then sprinkle with chopped basil. Drizzle with a small amount of balsamic vinegar if desired. Allow the chicken to rest 5 minutes before serving.