Bring a large pot of salted water to a boil. Cook the penne pasta according to package instructions. Drain and rinse with cold water to cool the pasta.
In a large mixing bowl, combine the cooled pasta, tomatoes, cannellini beans, mozzarella pearls, basil, and spinach.
In a small bowl, whisk together the lemon juice, olive oil, salt, and pepper.
Pour the dressing over the pasta salad and toss until everything is evenly coated.
Serve immediately or refrigerate for 30 minutes to let the flavors meld together. Garnish with extra basil before serving if desired.
