Here, grilled ham and cheese meets French toast for an extracrispy, sweet -and -salty combo that's hard to resist. Serve it plain or drizzled with maple syrup.
Have your child spread 1 slice of bread with the mustard. Then layer on 1 slice of cheese followed by both slices of ham and the last piece of cheese. Spread the jam or jelly on the other piece of bread, then press it, spread side down, onto the sandwich.
Use a piece of paper towel to rub an unheated heavy skillet with a little cooking oil. Place the skillet over moderate heat.
As the skillet heats, have your child whisk the eggs, milk, and salt in a shallow bowl until frothy.
Put the butter in the center of the pan. As it starts to melt, have your child hold the sandwich together firmly and briefly submerge one surface in the egg batter then twist his wrist and submerge the other surface.
Immediately place the sandwich in the pan, before the butter browns. Grill the sandwich on the first side for about 3 minutes, until golden brown. Then flip it with a spatula and grill it on the second side for another 3 minutes.
Using a spatula, transfer the sandwich from the pan to a plate, slice it in half, and serve.