Pinwheel Meatloaf

Preheat oven to 350 degrees F (175 degrees C). Make the filling: Coarsely chop the spinach, and place in a large bowl; set aside. Heat butter in a large heavy skillet over medium heat. Saute mushrooms and onion until onion is translucent. Transfer mushroom mixture to bowl with spinach. Mix in 1/2 cup bread crumbs, 1 egg and parsley. Season with salt, pepper and nutmeg. In a large bowl, combine ground beef, ground pork, Cheddar cheese, 1/2 cup bread crumbs, 1 egg. Season with Worcestershire sauce, salt and pepper. Place meat mixture between two sheets of waxed paper, and roll into a rectangle approximately 18x8 inches. Remove top sheet. Spread spinach mixture evenly over meat, leaving a 1/2 inch border. Roll up meat from the short end in jelly-roll style, lifting and removing paper as you go. Place loaf into an 8x4 inch loaf pan. Bake in preheated oven for about 1 hour, or until browned and juices run clear. Serve hot or cold.