Start by preheating your oven to 350°F (175°C). Gather all your ingredients.

Bring a large pot of salted water to a boil and add the jumbo pasta shells. Cook until al dente, about 8-10 minutes. Drain and rinse with cold water.

In a large skillet over medium heat, cook the ground beef for about 6-8 minutes until browned. Drain excess fat.

In a separate mixing bowl, combine mozzarella and provolone cheeses. Mix well.

In a large bowl, mix ricotta, half of the cheese blend, Italian seasoning, garlic powder, onion powder, beaten egg, Parmesan, salt, and pepper. Fold in the browned beef.

Spray a 9 x 13-inch baking dish with cooking spray and spread a layer of marinara sauce at the bottom.

Stuff each cooked pasta shell with the beef and cheese filling and place them seam side up in the baking dish.

Pour remaining marinara sauce over the filled shells and sprinkle with remaining cheese.

Cover with aluminum foil and bake for 20 minutes. Remove foil and bake for an additional 10 minutes.

Let cool for a few minutes, serve hot, garnished with fresh parsley and extra Parmesan cheese if desired.