In a food processor, blend the basil leaves, pine nuts, garlic, Parmesan cheese (if using), salt and pepper. After about 10 seconds – while the machine is still in motion – stream in the olive oil very slowly. Continue to mix until well blended.

Cook the pasta according to package directions. Drain and toss with pesto.

Add the tomatoes and pine nuts and toss again.

Serve at room temperature.