Prepare the ingredients: Lightly toast the pine nuts in a dry pan over medium heat until fragrant (about 3-5 minutes). Set aside to cool slightly. If using, blanch the garlic scapes in boiling water for 30 seconds, then immediately transfer to an ice bath to stop cooking; drain well.

Make the pesto: In a food processor, combine the blanched garlic scapes, fresh basil, cooled pine nuts, salt, pepper, and optional fresh garlic clove. Pulse until coarsely chopped.

Emulsify the pesto: With the food processor running, slowly drizzle in the 1/2 cup of olive oil until a thick, bright green paste forms. Stop processing and transfer the mixture to a medium bowl.

Finish the pesto: Stir in the grated Parmesan cheese. Taste and adjust seasoning with more salt or pepper if necessary. Set aside while you cook the pasta.

Cook the pasta: Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions until al dente. Before draining, reserve at least 1/2 cup of the starchy pasta water.

Combine and serve: Drain the pasta well and immediately transfer it to the bowl containing the pesto. Add 1/4 cup of the reserved pasta water and toss vigorously until the pesto loosens and coats the pasta beautifully. Add more pasta water, a tablespoon at a time, until desired consistency is reached. Serve immediately, perhaps with an extra drizzle of olive oil or cheese on top.