Peel and trim onion, carrot, garlic and fennel (or celery). Pulse in food processor to a fine dice. Heat olive oil in a sauté pan. Sauté onion, carrot, garlic and fennel/celery til soft, about 7 minutes.
Mix meat together thoroughly in a large bowl. (Hands work best).
Add the spices and egg to the meat mixture and mix thoroughly.
Add the onion mixture and mix thoroughly.
Add the bread crumbs and parmesan and mix thoroughly.
Preheat oven to 350°. Prepare a rimmed pan by spraying with cooking spray. Place a wire rack over the rimmed pan. (If you don't have a wire cooking rack then line the rimmed pan with foil. Make sure pan is quite a bit bigger in surface area than the meatloaf shape.)
Line a casserole dish large enough to hold the mixture with plastic wrap. Pack the meatloaf mixture into casserole dish.
Invert the meatloaf onto the wire rack. Remove the plastic wrap. Set the casserole dish aside ensuring there is no no raw meat contamination. You can store you meatloaf in the casserole dish when it is done baking.
Carefully pour the marinara sauce over the top of the meatloaf. Use a spatula to get sauce to adhere to the sides of the meatloaf.
Bake until meat reaches 160° internal temperature. Mine took 1 hour and 40 minutes. Time will depend on the shape/depth of your meatloaf.
Remove from oven. Allow to rest 5 minutes. Transfer meatloaf to a platter, slice and serve. You can serve additional marinara sauce on the side if desired.