Bring a large pot of salted water to a boil and cook the pasta until al dente, according to package instructions. Reserve 1 cup of the pasta water. Use a colander to drain the pasta. Return to pot or place in a large serving bowl.

In a blender or food processor, combine the pesto, cottage cheese, and 1/2 cup of reserved pasta water. Blend until smooth. Season with salt and pepper, to taste.

Add the creamy pesto sauce to the pasta and stir until pasta is well coated. Garnish with crushed red pepper flakes, fresh basil, and Parmesan cheese, if desired. Serve warm.