1. Preheat the oven to 450°F.
2. Place chicken on the prepared baking sheet. Spoon some marinara sauce on each piece of chicken and top with a few leaves of fresh basil and 2 slices of fresh mozzarella.
3. Place the thawed broccoli in a medium bowl. Add the olive oil and season with salt and black pepper. Toss to coat. Arrange the broccoli around the chicken.
4. Bake the chicken and broccoli for 12 to 15 minutes, or until the chicken is heated through and the cheese is melted. The broccoli should be beginning to brown. If desired, place the baking sheet under the broiler for 1 to 2 minutes for additional browning.
5. Squeeze the lemon over the broccoli. Sprinkle everything with crushed red pepper and top with grated parmesan cheese and fresh basil. Serve right away with cooked pasta, if desired.