Creating the perfect meatloaf with mushroom gravy is easy if you follow these detailed steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and lightly grease a loaf pan or baking sheet.
2. Prepare the Meatloaf Mix: In a large mixing bowl, combine the ground beef, breadcrumbs, milk, chopped onion, minced garlic, egg, Worcestershire sauce, Dijon mustard, salt, pepper, and thyme (if using). Mix until just combined—do not overmix.
3. Shape the Meatloaf: Transfer the meat mixture to the prepared loaf pan or shape it into a loaf on the baking sheet. Make sure it is evenly shaped.
4. Bake the Meatloaf: Place the meatloaf in the preheated oven and bake for 45-50 minutes or until the internal temperature reaches 160°F (70°C).
5. Let it Rest: Remove the meatloaf from the oven and allow it to rest for about 10-15 minutes before slicing.
6. Prepare the Mushroom Gravy: While the meatloaf is resting, melt 2 tablespoons of butter in a skillet over medium heat. Add the sliced mushrooms and cook until tender, about 5-7 minutes.
7. Make the Gravy: Sprinkle the flour over the cooked mushrooms and stir well. Gradually pour in the beef broth while stirring. Bring to a simmer until the mixture thickens. Add the heavy cream, stirring until well combined. Season with salt and pepper to taste.
8. Serve the Meatloaf: Slice the meatloaf and generously ladle the mushroom gravy over each slice.

By following these steps, you’ll create a delightful meatloaf immersed in rich mushroom gravy that will wow everyone at your dinner table.