Preheat oven to 350°.
Mix beef, pork, soup mix, eggs, bread crumbs, pepper and water. Use your hands, mix it thoroughly. Stir in ½ cup of mozzarella and mix well.
Place half the meat loaf into a lightly greased 9x5 loaf pan. Dent the center slightly then spread the remaining 1 ½ cups of mozzarella evenly over the meat loaf. Top this with the remaining mixture. You can try to seal the sides, but I guarantee the cheese will leak out no matter what you do.
Bake in preheated oven for 1 hour. Cool for at least 20 minutes before trying to serve. It will come apart in a catastrophic act of cheesy self-destruction if you don't wait.