Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup. If chicken breasts are very thick, place them between two pieces of plastic wrap and gently pound to an even 1/2-inch thickness.
Step 2: Pat the chicken breasts dry with paper towels and season both sides lightly with salt and pepper. Keep in mind that pesto is often salty.
Step 3: Generously spread about 2 tablespoons of pesto over each side of the chicken breasts, ensuring they are fully coated.
Step 4: Arrange the pesto-coated chicken breasts on the prepared baking sheet. Scatter the cherry or grape tomatoes around the chicken.
Step 5: Drizzle the tomatoes with 2 tablespoons of olive oil and season them lightly with salt and pepper. Ensure everything is in a single layer for even roasting.
Step 6: Bake for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F (74°C). Cooking time may vary based on chicken thickness. Use a meat thermometer for accuracy.
Step 7: If using, sprinkle the mozzarella or Parmesan cheese over the chicken during the last 5 minutes of baking, allowing it to melt and become lightly golden.
Step 8: Remove the Pesto Baked Chicken with Tomatoes from the oven and let it rest for 5-10 minutes before slicing. This helps the juices redistribute, keeping the chicken moist and tender. Garnish with fresh basil, if desired, and serve warm.