Best Monte Cristo Sandwich

Assemble four sandwiches using bread, meats, and cheeses. Set aside. In medium mixing bowl (I use a square casserole dish), combine egg, water, milk, salt, sugar, flour, baking powder & mustard. Beat well. Heat about 1" of oil in deep skillet (I use a large iron skillet). Dip your sandwiches into the coating mixture, I like to get them well soaked. They will be drippy -- try to drain off a bit, carefully slide into the hot oil. Repeat with remaining sandwiches. When nicely browned, gently flip over & brown other side. Remove to paper towels. Sprinkle with powdered sugar. Let cool a few minutes before cutting so the cheese doesn't ooze out. Cut each sandwich into four fingers for easy dipping. Serve with syrup or jam.