Gather ingredients.

Preheat the oven to 250 degrees F (120 degrees C).

Using tongs, place bread slices directly on the oven racks in the preheated oven. Leave in the oven until hard and golden brown, about 30 minutes; darker if you prefer. Remove bread and cool on a wire rack.

Crumble slices into a large bowl until reduced to fine crumbs, or place in the bowl of a food processor and pulse until fine.