Hidden Protein Pasta Sauce

0 Cook the lentils according to package directions until tender. 
1 Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions for al dente. Reserve about 1 cup of the cooking water, then drain the pasta.
2 Meanwhile, combine the marinara sauce and cottage cheese in a high-speed blender. Add the cooked lentils and blend until completely smooth. 
3 Pour the sauce into the now-empty pasta pot and and set over low heat. Add just enough pasta water until the sauce reaches your desired consistency. Taste and season with salt, if needed. 
4 Add the cooked pasta and toss until evenly coated. Cook, stirring occassionally, until warmed through, adding more pasta water as needed to loosen the sauce.