Cook pasta shells: Boil the jumbo shells according to package instructions, drain, and set aside.
Sauté spinach: Heat olive oil in a skillet, sauté spinach until wilted (2-3 minutes), then remove from heat.
Make the filling: In a bowl, mix ricotta, mozzarella, Parmesan, cream cheese, egg, sautéed spinach, chopped artichokes, garlic powder, onion powder, salt, and pepper.
Stuff the shells: Stuff each cooked pasta shell with the filling.
Assemble the dish: Preheat oven to 375°F (190°C). Spread marinara sauce in a baking dish, arrange stuffed shells, and pour remaining sauce on top. Sprinkle mozzarella cheese over the shells.
Bake: Cover with foil and bake for 25 minutes. Remove foil, bake for 10 more minutes.
Garnish and serve: Let cool briefly, garnish with fresh parsley, and enjoy!