Add ground Italian sausage to skillet over medium heat. Break into small pieces. Cook until fully done.
Once sausage is done, add sausage, ricotta, mozzarella, parmesan, egg, Italian seasoning, garlic powder, and black pepper into a large bowl. Mix thoroughly.
For The Pasta
Heavily salt a pot of water; bring to a boil.
Once boiling, add jumbo pasta shells to the water. Cook for roughly 3 minutes, just enough time for shells to soften. This will allow you to properly stuff the shells with filling.
To Complete The Recipe
Pour 3/4 jar of choice of marinara sauce into an oven-safe dish. Add in red pepper flakes and garlic powder. Mix well with a spoon.
Add filling liberally into each shell. Place shell in marinara. Repeat until done.
Add the remaining 1/4 jar of marinara to the top of the shells. Top with 1/2 c. of mozzarella. Bake for 35-40 minutes. Serve and enjoy!