Creating the incredible Meatloaf with Mushroom Gravy is simple if you follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Prepare the Meat Mixture: In a large bowl, combine the ground beef, breadcrumbs, egg, onion, garlic, Worcestershire sauce, ketchup, thyme, salt, pepper, milk, and Parmesan cheese (if using). Mix until fully combined.
3. Form the Loaf: Shape the meat mixture into a loaf and place it in a greased baking dish or on a baking sheet lined with parchment paper.
4. Bake the Meatloaf: Bake in the preheated oven for 50-55 minutes, or until the internal temperature reaches 160°F (70°C).
5. Sauté the Mushrooms: While the meatloaf is baking, melt butter in a skillet over medium heat. Add the sliced mushrooms and cook until they are soft and browned, about 5-7 minutes.
6. Make the Gravy: Sprinkle the flour over the mushrooms and stir to combine. Gradually pour in the beef broth and soy sauce, stirring constantly until the gravy thickens. Season with salt and pepper to taste.
7. Rest the Meatloaf: Once the meatloaf is done baking, remove it from the oven and let it rest for about 10 minutes before slicing.
8. Serve with Gravy: Slice the meatloaf and serve it warm, topped with the mushroom gravy.

This straightforward process will guide you in creating an amazing Meatloaf with Mushroom Gravy that everyone will love.