Preheat the oven to 350°F (175°C). In a large bowl, combine the ground beef, ground pork, breadcrumbs, milk, ketchup, onion, bell pepper, eggs, Worcestershire sauce, garlic powder, salt, black pepper, thyme, and oregano. Mix until well combined.

Shape the meat mixture into a loaf and place it in a greased 9x5-inch loaf pan or on a baking sheet lined with parchment paper.

Bake in the preheated oven for 1 hour or until the internal temperature reaches 160°F (70°C). Remove from the oven and let it rest for 10 minutes before slicing.

While the meatloaf is resting, heat olive oil in a skillet over medium heat. Add the sliced mushrooms and sauté until they are browned and tender, about 5-7 minutes.

Pour in the beef broth and bring to a simmer. Stir in the cornstarch mixture and cook until the gravy thickens, about 2-3 minutes. Season with salt and pepper to taste.

Serve slices of meatloaf topped with mushroom gravy and garnish with fresh parsley.