How to Make It
Preheat oven to 375°F. Coat a 13- x 9-inch baking dish with cooking spray; set aside.
Stir together mayonnaise, mustard, maple syrup, and 1/4 teaspoon of the salt in a small bowl. Using a long serrated knife, split the entire loaf of rolls horizontally (do not separate individual rolls from each other). Spread mayonnaise mixture on both cut sides of rolls. Fold ham slices; arrange ham and cheese evenly on bottom rolls. Replace top rolls.
Brush tops of rolls evenly with butter; sprinkle with bagel seasoning and remaining 1/4 teaspoon salt. Cover baking dish with aluminum foil. Bake in preheated oven 8 minutes. Remove foil; continue baking until cheese is melted and rolls are golden brown, 5 to 7 minutes. Serve immediately.