Break the bread into pieces, drop into the food processor or blender, and grind until fairly fine, for about 30 seconds (in blender) to 3 minutes (in food processor).
Use immediately or store in a tightly-covered container in the fridge for up to a week, or in the freezer for a couple of months.
For more flavor and color, stir in up to a T of dried herbs and/or spices after grinding.
*After destroying two spice grinders and a cheap blender, I found that the very best tool for making bread crumbs, whether the bread is stale or fresh, is with the dry blade container of my Vitamix.
**No stale bread? Try one of these options:
- Toast fresh bread until golden brown, cool, and grind.
- Bake fresh bread on at 250° for 30 minutes, cool, and grind.
- Fairly dense bread (like a whole-wheat baguette) can be ground when fresh.