Preheat the oven to 375°F (190°C).
Cook the pasta shells according to package instructions until al dente.
Prepare the filling by combining ricotta, mozzarella, Parmesan, basil, parsley, garlic powder, salt, and pepper in a bowl.
Drain the pasta and allow it to cool slightly.
Stuff each pasta shell with the cheese filling.
Spread half of the marinara sauce in a baking dish, then place the stuffed shells on top.
Top the stuffed shells with the remaining marinara sauce and sprinkle extra mozzarella and Parmesan on top.
Cover the baking dish with aluminum foil and bake for 25 minutes.
Remove the foil and bake for an additional 10-15 minutes until the cheese is bubbly and golden.
Let cool for a few minutes before serving.