First, prep the chicken. In a large bowl, combine olive oil, vinegar, lemon juice, Dijon mustard, garlic powder, 1 teaspoon salt, and 1/4 teaspoon pepper. Whisk until smooth.
1/2 cup olive oil, 3 Tablespoons balsamic vinegar, 1 Tablespoon lemon juice, 1 Tablespoon Dijon mustard, 1 teaspoon garlic powder, kosher salt and black pepper
If needed, cut the chicken breasts lengthwise through the middle to make them fairly thin. If any pieces are really uneven, use a meat mallet or just a heavy pan to smash down the thick parts and even them out. Add chicken to the marinade and turn to coat. Cover and transfer to the fridge for at least 20 minutes and up to 8 hours.
4 boneless, skinless chicken breasts
Grill or pan-fry. When ready to cook, remove chicken and discard the marinade. Grill or saute in a large skillet over medium-high heat, flipping to cook for 3-5 minutes on each side, until cooked through to 165°F. Transfer chicken to a clean plate.
Put it together. While the chicken is cooking, drain the mozzarella and use a clean kitchen towel or paper towel to dab off some of the excess moisture.
6-8 ounces fresh mozzarella
Cut the tomatoes in half, and toss them in a bowl together with about 2 teaspoons olive oil, 1 teaspoon balsamic vinegar, a big pinch each of salt and pepper, and a handful of slivered basil leaves. Add more of anything to taste.
1-2 cups cherry or grape tomatoes, olive oil, balsamic vinegar, fresh basil leaves
To serve, top chicken with mozzarella and tomatoes. Sprinkle with extra balsamic, basil, salt, or pepper to taste. Enjoy!