Toast the pine nuts in a dry skillet over medium heat for 2-3 minutes until lightly golden and fragrant, then set aside to cool.
In a food processor, combine the basil, toasted pine nuts, garlic, and Parmesan. Pulse until roughly chopped.
With the processor running, slowly drizzle in the olive oil until the pesto is smooth but still has some texture. Season with salt and pepper.
Bring a large pot of salted water to a boil. Cook the fusilli according to package directions until al dente, about 8-10 minutes.
Drain the pasta and toss it with a tablespoon of olive oil to prevent sticking. Let it cool slightly if serving warm.
In a large bowl, combine the cooked pasta, pesto, halved cherry tomatoes, and mozzarella pearls. Toss gently to coat everything evenly.
Squeeze the lemon juice over the salad and toss again. Taste and adjust seasoning with more salt or pepper if needed.
Let the salad sit for 10 minutes to allow the flavors to meld before serving.
