Preheat your oven to 375°F (190°C). Lightly spray a 9x13-inch baking dish with cooking spray and set it aside.

Cook the jumbo pasta shells according to the package instructions. Once cooked, drain them and let them cool. Make sure they are al dente so they hold up well when stuffed.

In a mixing bowl, combine the cottage cheese, grated parmesan cheese, egg, dried parsley, and 1 cup of the shredded mozzarella cheese. Mix well until everything is combined. For an extra kick of flavor, consider adding some Italian seasoning or garlic powder to this mixture.

Carefully stuff each pasta shell with the cheese mixture and place one meatball inside each shell. Arrange the stuffed shells in the prepared baking dish. Take your time with this step to avoid tearing the shells.

Pour the spaghetti sauce over the stuffed shells, ensuring they are well covered. Sprinkle the remaining mozzarella cheese on top to create a golden, bubbly crust.

If you want to save this dish for later, you can freeze it at this point. Otherwise, bake in the preheated oven for 25-30 minutes, or until the dish is bubbly and the cheese is melted. Keep an eye on it to prevent over-browning.