Steps
1. Cook the spaghetti in a large pot of salted boiling water according to package instructions until al dente.
2. While the pasta cooks, prepare the pesto by blending the basil, garlic, pine nuts, Parmesan cheese, and olive oil in a food processor until smooth.
3. Season the pesto with salt and pepper to taste.
4. Drain the pasta and reserve a little pasta water. Toss the spaghetti with the pesto, adding reserved water if needed to loosen the sauce.
5. Serve hot, garnished with halved cherry tomatoes and extra Parmesan if desired.