Step 1In a large pot of boiling salted water, cook pasta, stirring occasionally, until al dente according to package directions. Drain; reserve 1/2 cup pasta water.
Step 2Meanwhile, in a blender, blend marinara, cottage cheese, Parmesan, and oil until smooth.
Step 3Return pasta to pot and add sauce and 1/4 cup reserved pasta water. Toss, adding more pasta water as needed, until pasta is coated and sauce is warmed through.
Step 4Divide pasta among bowls. Top with Parmesan.