Preheat oven to 350 degrees.
Boil the shell noodles according to the package directions. Drain and set aside.
Brown and drain the ground beef.
After you drain the grease from the ground beef, add the diced onions and sauté with the beef until the onions are soft.
Mix in the fennel and salt, and sauté for another minute or so.
Remove from the heat, then mix in garlic powder, oregano, tomato sauce, and Parmesan cheese, and stir until thoroughly combined.
Add the shell noodles to the meat mixture and combine thoroughly.
Spray the bottom of your 10x14-inch baking dish with nonstick spray, then toss a handful of mozzarella to cover the bottom.
Add a thick layer of the noodle/meat mixture to the baking dish.
Add a layer of mozzarella.
Then add the rest of the noodle/meat mixture on top of the mozzarella.
Top with the remaining mozzarella and bake in the oven at 350 dgrees for 35- 40 minutes.
Enjoy.