Grate the parmesan cheese and either mix in by hand or place into the food processor and blend again. Set the basil pesto to the side while cooking the pasta.
Bring a saucepan full of water to the boil, season with a few pinches of salt. Place the pasta into the water and cook until al dente. Reserve a cup of the starchy cooking water.
Mix in half of the basil pesto with a small amount of the starchy cooking water. Toss together. Add the remaining basil pesto and toss until everything is well combined.