Cut your stale bread into large cubes. You can leave the crust on or remove it. I removed the bottom only because it was very thick and dark. I left the rest of the crust on.
Place in a food processor and pulse until the crumbs are what you desire.
Pour onto an ungreased baking sheet and level crumbs so they are evenly dispersed
Bake in a preheated 300°F oven until fully dry stirring the crumbs every 10 minutes
Once the breadcrumbs are fully dry, allow them to cool on the baking sheet then place them in an airtight container
Notes
Use any type of leftover stale bread. Each type of bread will produce a different crumb and a different taste.
Finer breadcrumbs can be achieved after the breadcrumbs are fully dried. Just place them back in a food processor and pulse.
After the breadcrumbs are cool, make certain they are fully dry. If not, place back into the oven for a few more minutes.
Store at room temperature in an airtight container