Gather your fresh basil leaves, garlic cloves, pine nuts, Parmesan cheese, extra virgin olive oil, and lemon juice. Rinse the basil thoroughly and peel the garlic.

In a food processor, combine the basil leaves, garlic, pine nuts, and grated Parmesan cheese. Pulse until finely chopped and drizzle in the olive oil while blending until smooth.

Bring a large pot of salted water to a rolling boil. Cook the spaghetti according to package instructions, typically around 8-10 minutes for al dente.

Combine the drained pasta with the pesto in a large mixing bowl while still warm. Toss until evenly coated, adding reserved pasta water if necessary.

Serve with halved cherry tomatoes and optional mozzarella, drizzled with olive oil.