Cook pasta shells according to package directions.  While they boil, preheat oven to 375 degrees and prepare a 9X13 inch baking dish by spreading 1/2 cup of marinara sauce on bottom. Set aside.

Chop cauliflower into tiny pieces; even better, place the florets into a food processor and rice it. Place chopped cauliflower in a microwave-safe bowl; add a 1/4 cup of water and cover loosely.  Steam in the microwave until it becomes softer.  Drain liquid and toss cauliflower into a large mixing bowl.  

Mince garlic, add to cauliflower.  Add egg, mozzarella (about 1/2 cups) and cottage cheese; season with salt and pepper. 

Place shells into baking dish; fill each with cheese mixture; top with remaining marinara sauce and shredded mozzarella cheese. 

Cover with foil and bake for 15-20 minutes, until bubbly.