Preheat oven to 350 degrees F. Spray a 9"x13" baking dish with cooking spray and set aside.

Cook sausage in a large skillet over medium-high heat, crumbling into very small pieces. Drain grease from the sausage and stir in the spaghetti sauce. Bring to a boil, then turn to low and simmer until ready to use.

Grate the zucchini using a cheese grater or food processor. Gather up shredded zucchini into a clean kitchen towel and wring out as much liquid as possible. Set aside.

In a small bowl, combine Ricotta, egg, Parmesan cheese and 1/2 of the Mozzarella cheese. Stir in a pinch of salt and pepper. Fold in zucchini.

Spoon half of the spaghetti sauce with the sausage into the preparred baking dish, spreading around to coat the bottom of the dish.

Using a cookie scoop or a spoon, fill pasta shells with the zucchini/cheese mixture. Arrange in a single layer in the baking dish on top of the sauce.

Spoon the remaining sauce over the shells and sprinkle with the grated Mozzarella cheese.

Bake in the 350 degree oven for 15-30 minutes, or until cheese is lightly browned and bubbly.

Garnish with fresh basil or parsley, if desired.