In a blender, combine basil leaves, pine nuts, Parmesan cheese, garlic, salt, and pepper. Blend until smooth.

With the blender running, slowly add olive oil until fully incorporated.

Bring a large pot of salted water to a boil. Add pasta and cook according to package instructions until al dente.

Reserve 1 cup of pasta water, then drain the pasta in a colander.

In a large skillet, combine the cooked pasta, pesto, cherry tomatoes, and spinach. Toss to combine, adding reserved pasta water as needed to reach desired consistency.

Serve immediately, garnished with additional Parmesan if desired.