I'm originally from Nebraska, and when I was a kid, there was a chain of restaurants called, "Kings Food Host". They made a sandwich that was incredible, called a "Cheese Frenchee". The actual recipe is a secret (in fact, even people that worked there say they didn't know ALL the ingredients). I searched, and experimented, and this is as close as it gets! The chain is now closed, sadly, but there are some restaurants in the midwest that still serve this yummy sandwich. They also made one with tuna, called...you guessed it....a "Tuna Frenchee".
Make 3 sandwiches using 2 slices of bread spread with Miracle Whip or mayo (Kings used Miracle Whip), and 2 slices of American cheese for each sandwich. Cut the crusts off, and then slice each sandwich diagonally, to make 4 triangles.
In a small bowl, combine the egg, milk, flour & salt and whisk to make a batter.
Dip each triangle in the batter, covering completely. Let the excess drip off, and then coat with crumbs.
Fry the triangles in 375 degree oil until golden brown.
*Note: If you are just making one sandwich for yourself, you can use the leftover batter & crumbs to make onion rings. They are wonderful!!