Start by combining the ground beef and ground pork in a large bowl. Season it with sea salt, black pepper, and onion powder. Mix well until all ingredients are evenly incorporated.

Shape the mixture into burger patties. Aim for a uniform thickness to ensure even cooking. The size can vary according to your preference—just remember they will shrink slightly during cooking.

In a large skillet, heat a bit of oil over medium heat. Once hot, add the patties. Cook for about 4-5 minutes on each side or until they’re browned and cooked to the desired doneness. Once done, remove patties and let them rest.

Using the remaining oil in the skillet, add the unsalted butter. Once melted, toss in the sliced mushrooms. Sauté for about 3-4 minutes, bringing out their flavor.

Sprinkle the flour over the mushroom mixture. Stir continuously to cook the flour, creating a roux. This step helps to thicken the gravy.

Gradually pour in the rich beef stock while whisking to avoid lumps. Continue to stir until the gravy thickens to your liking.

Once thickened, season with salt, black pepper, Worcestershire sauce, and fresh thyme. Allow everything to simmer together for a few minutes to meld the flavors.

Plate your burger patties and generously spoon the mushroom gravy over them. Serve with steaming rice or mashed potatoes to soak up all that flavor. Don’t forget a fresh garnish to make it visually appealing!