Preheat oven to 300°F (150°C).
Tear bread slices into small, rough pieces.
Spread bread pieces in a single layer on a parchment-lined baking sheet.
Bake for 10–15 minutes, stirring once halfway through, until bread is completely dry and lightly golden.
Remove from oven and allow to cool completely.
Transfer dried bread pieces to a food processor.
Pulse 10–15 times until crumbs reach your desired consistency (coarse or fine).
(Optional) For seasoned crumbs, toss processed crumbs with olive oil, salt, garlic powder, and Italian herbs. Spread back on the baking sheet and bake at 350°F for 5–7 minutes until golden and fragrant.
Let cool completely before transferring to an airtight container.