Making bread crumbs is a great way to make use of hamburger buns when you have too many of them on hand or they aren't as fresh as you prefer for sandwiches. The buns need to be completely dry so they can be ground up properly a food processor, but you don't want to use ones that are totally stale, because the crumbs will taste stale too. You can also combine different types of buns -- like whole wheat or whole grain -- with white hamburger rolls when making bread crumbs.
Tear the dry hamburger buns into very small pieces and put them in a blender or food processor. (If the buns aren't completely dry, heat them in the oven at 350 degrees Fahrenheit for 10 minutes and let them cool before shredding them into pieces.)
Put the lid on the blender or food processor and turn it on to the Grind setting.
Grind the bread pieces until they are very fine. During the grinding process, turn off the processor and shift the bread around with a wooden spoon to ensure that all of it is ground into fine pieces. Repeat as necessary.
Pour the bread crumbs into a plastic container with a lid. Store them in the freezer or the pantry.