Preheat the oven by setting it to 400°F. Take a 9x13-inch baking dish. Spread marinara sauce, on its surface.
Next, cook the shells in salted water for 6 to 7 minutes. Then drain them properly.
In a mixing bowl combine ricotta cheese, Parmesan cheese, egg, your favorite seasoning, garlic, salt and a pinch of pepper. Mix well. Add some chicken to enhance the flavor.
Now it's time to fill the shells with this mixture. Dip each stuffed shell into butter. Then coat them with panko crumbs. Place these shells in the baking dish with the side facing up.
Bake the shells in the preheated oven for 20 minutes until the breadcrumbs turn brown. If you prefer a slightly crispy texture on top you can broil them for 3 to 5 minutes.
Once baked to perfection sprinkle some mozzarella cheese on top of the shells. Bake for another 5 minutes until it melts beautifully.
Finally serve these mouthwatering stuffed shells warm, from the oven. Enjoy every bite.