Coat a large griddle or skillet with cooking spray and preheat to medium heat.
Spread mustard on 4 slices of bread. Spread mayonnaise on remaining 4 slices of bread. Top mustard side of slices with pear slices, ham and cheese. Place second slice of bread (with the mayonnaise) over top, making a sandwich.
In a shallow dish, whisk together eggs, salt, cinnamon, baking powder and water. Dip sandwiches in egg mixture and turn to coat both sides. Place sandwiches on hot griddle and cook 3 to 5 minutes per side, until egg is cooked and cheese melts.