Place 6 bread crusts on a large plate in two stacks of three.

Cover bread crusts with a colander to allow airflow to quickly dry them out while also providing some protection. Leave on the counter until they are hard from drying out.

How long this takes will depend on the humidity in your home. In my house, it only takes 24 hours or so. Even if it takes a couple of days, the breadcrumbs turn out fine!

Alternatively, you can dry them more quickly in a dehydrator or a warm (150F) oven or placing on a plate on a warm (not hot) stovetop. Sitting on the counter works fine though!

Break bread crusts into quarters and process until desired size in the food processor. Pulse a few times for panko breadcrumbs and pulse continuously until finely ground for traditional breadcrumbs.

Alternatively, if you don't have a food processor, tear the crusts into the smallest pieces possible and pound them into the desired size crumbs in a mortar & pestle.

Place breadcrumbs in an airtight container and refrigerate. Using glass will help them keep longer.