Make the Pesto: Add fresh basil leaves, toasted pine nuts, grated Parmesan cheese, and minced garlic into a food processor. Pulse until finely chopped, then drizzle in olive oil while running the processor until smooth. Season with salt and pepper.

Cook the Pasta: In a pot of salted boiling water, cook rotini pasta according to package instructions, about 8-10 minutes. Drain and rinse under cold water.

Combine Ingredients: In a mixing bowl, combine cooled pasta, pesto, halved cherry tomatoes, and mozzarella balls. Toss gently until evenly coated.

Serve or Chill: Serve immediately or cover and refrigerate for 30 minutes to meld flavors. Toss before serving.