Preheat oven to 375°F. Boil pasta as per box instructions, until al dente. Set aside.
Mix all sauce ingredients in a baking dish. Cover with foil and bake for 35 minutes.
While sauce is baking, mix all filling ingredients in a large bowl.
Fill cooked pasta shells with filling mixture using a spoon or piping bag.
Remove sauce from the oven and mash with a fork, making sure to combine all ingredients together.
Assemble stuffed shells on top of the sauce and sprinkle with remaining mozzarella. Cover with foil and bake for 25 mins. Remove foil and broil for 3-5 mins or until cheese is golden. Serve.