Preheat oven to 375F degrees. Boil pasta 3 minutes less than package directions state. Mine said to cook for 8-10 minutes, so I cooked my shells for 5 minutes.
Mix in garlic and herb cheese, cottage cheese, 3/4 cup mozzarella, 2 tbsp parmesan, seasonings, and egg in a large bowl. Add in drained pasta and mix together until pasta is fully coated.
Coat a 13x9 baking dish with cooking spray, then add in two cups of marinara and spread until it evenly covers the bottom of the dish.
Add the pasta and cheese mixture to the dish. Spread evenly across the marinara sauce.
Top pasta/cheese mixture with another 1 -2 cups of marinara, depending on how saucy you like your pasta.
Sprinkle remaining 1/2 cup mozzarella and 2 tbsp parmesan over the top of the casserole. Bake, uncovered, for 30-40 minutes, or until cheese is bubbling at the tops of the shells have started to brown.
Divide into 8 servings, about 2 cups of shells and sauce combined.