Preheat the oven to 375°F (190°C).
Cook jumbo pasta shells according to package instructions until al dente. Drain and set aside to cool.
In a bowl, combine ricotta cheese, beaten egg, chopped fresh parsley, minced garlic, salt, and black pepper. Mix until smooth.
Stuff each pasta shell generously with the ricotta mixture.
Spread a layer of marinara sauce evenly in the bottom of a baking dish.
Arrange the stuffed shells in a single layer over the sauce.
Spoon additional marinara sauce evenly over and around the shells.
Sprinkle shredded mozzarella and parmesan cheese evenly on top.
Bake uncovered for 30-35 minutes or until the cheese is melted and golden brown.
Remove from oven and let rest for 5 minutes before serving.
Plate the shells on a round white ceramic plate, spooning sauce over and around them, and sprinkle with chopped fresh parsley.