Preheat oven to 350 degrees.

Butter the insides of the buns. Place hamburger buns butter-side up on a cookie sheet. If using mustard, put a little bit on the bottom bun.

Place ham on top of the bottom part of the bun. As much or as little as you want.

Place cheese on top of the ham.

Bake sandwiches for about 10 minutes until cheese is melted and buns are slightly toasted.

Put top of bun on top of the sandwich.

Eat!