Heat up oil in a pan. Cook the chopped onions until translucent. Add the fresh spinach, season with garlic powder, Italian Seasoning, salt & pepper, and few drops of Worcestershire sauce. Stir around a few times. Stir in the sliced mushrooms. Cook for a couple more minutes. Set aside.Preheat the oven to 355° In a large mixing bowl, combine the beef, beaten egg, few drops of Worcestershire sauce, Italian Seasoning, garlic powder, salt & pepper. Mix everything together with your hands.
I almost forgot the breadcrumbs. Continue to mix everything together with your hands.
Flatten the meat mixture into a clean cutting board. TIP: Use a rolling pin to get a smooth surface.
Distribute the spinach & mushrooms stuffing on top, evenly.
Add slices of cheddar cheese. Feta cheese or goat cheese would be great too. But if you don’t have any of them, regular Kraft cheddar slices would do.
Slowly and carefully roll the meat with stuffing.
Carefully transfer the rolled stuffed meatloaf into a large baking pan. Cover with foil and bake for 45 minutes.
While the stuffed meatloaf is cooking, make your sauce topping. In a bowl, whisk together the ketchup, brown sugar, spicy brown mustard and nutmeg. Whisk until well-incorporated then set aside.
After baking for 45 minutes, take the baking pan out, take the foil off, then generously brush the top of the meatloaf with the topping. Put it back in the oven to bake for another 20-25 minutes.
After the last baking, take the pan out of the oven and let it cool for 5 minutes or so. Transfer it in a serving platter. Slice diagonally.