How are the mini cheeseburgers made?

Are there any secrets to the mini cheeseburgers? Here's my best guess: they take a yeast roll, put some regular butter on it, toast it, then add a standard small burger patty and cheese. Are there any secrets I'm missing? Seasoning on the burger patty?

I realize this question probably sounds stupid but they are my favorite food and I would like to identify why I like them so much better than other burgers. I bet it's the rolls.