Step 1Heat the oven to 350 degrees and line a rimmed baking sheet with foil.
Step 2In a heavy sauté pan heated over medium-high heat until hot, melt the butter, then add the onions and Creole spice and sauté until softened, about 3 minutes. Add the garlic and mushrooms and cook until the mushrooms are softened, 3 to 5 minutes. Remove from heat and pour the mixture in a bowl. Set aside until cooled.
Step 3In a large bowl, knead together the beef, turkey, bread crumbs, egg, mushroom mixture, parsley, 2/3 cup ketchup, 2 dashes Worcestershire sauce, salt and pepper until well combined. Form the mixture into 2 loaves and place on the prepared pan.
Step 4In a small bowl, whisk together the remaining 2/3 cup ketchup, 2 dashes Worcestershire and 2 dashes Tabasco sauces. Spoon the ketchup mixture evenly over the loaves.
Step 5Bake the loaves until a thermometer inserted reaches 155 degrees, about 45 minutes. Increase the oven temperature to 425 and continue baking until a thermometer inserted into the meatloaf reaches 165 degrees, about 5 minutes.
Step 6Remove and set aside for several minutes to set up before slicing. While the meatloaf is resting, prepare the gravy.
Step 1In a large, heavy sauté pan heated over medium-high heat, melt 2 tablespoons butter. Add the onions and mushrooms, salt, pepper and Creole spice and cook, stirring frequently, until browned, 6 to 8 minutes.
Step 2Stir in the remaining butter, then sprinkle over the flour, stirring to make sure there aren’t any lumps. Slowly stir in the beef broth.
Step 3Reduce the heat to a gentle simmer and cook, stirring occasionally, until the gravy is thickened, about 30 minutes. Remove from heat and strain out the mushrooms and onions, discarding them. This makes about 2 cups gravy.