Toast pine nuts in a dry skillet over medium heat for 3-5 minutes, tossing frequently, until lightly golden brown and fragrant. Alternatively, toast in the oven at 350°F (175°C) for 5-7 minutes, watching carefully. Let cool slightly.

In a food processor, combine basil leaves, toasted pine nuts (or untoasted), and minced garlic. Pulse to coarsely chop.

Add Parmesan cheese (and Pecorino Romano, if using) to the food processor. Pulse to combine.

With the food processor running, slowly drizzle in olive oil until the pesto reaches your desired consistency.

Season with salt and pepper to taste.

Fill a large pot with water (at least 6 quarts). Add a generous pinch of salt. Bring to a rolling boil.

Add pasta and cook according to package directions (8-12 minutes) until al dente.

Before draining, reserve about 1 cup of pasta water.

Drain pasta in a colander (do not rinse).

Add drained pasta back to the pot. Add pesto and toss gently to coat.

If the sauce is too thick, add pasta water, one tablespoon at a time, until the desired consistency is reached.

Taste and adjust seasonings as needed.

Serve pesto pasta immediately.

Garnish with extra Parmesan cheese, halved cherry tomatoes, and a drizzle of olive oil. Add red pepper flakes for heat. Toss with cooked chicken or shrimp, if using.