01 - Cook the pasta in a large pot of salted boiling water according to package instructions until al dente. Reserve 1/2 cup pasta water and drain the rest.
02 - Heat olive oil in a large skillet over medium-high heat. Add the chicken pieces, season with salt and pepper, and sauté until golden and cooked through, about 6-8 minutes. Transfer chicken to a plate and set aside.
03 - In the same skillet, reduce heat to medium and add the butter. Sauté garlic for 1 minute until fragrant.
04 - Pour in the heavy cream and bring to a gentle simmer. Stir in the pesto and Parmesan cheese, mixing well until cheese melts and sauce is smooth.
05 - Return the cooked chicken to the skillet. Add drained pasta and cherry tomatoes if using. Toss to coat everything in the creamy pesto sauce. If the sauce is too thick, add reserved pasta water a splash at a time for desired consistency. Taste and adjust seasoning with salt and pepper. Serve immediately, garnished with extra Parmesan and fresh basil.