Preheat the oven to 350 degrees, use convection if possible.
Line a baking sheet with foil and set aside.
If your bread is not stale, lightly toast it in a toaster or toaster oven. When cool enough to handle, remove the toast and gently tear into small pieces.
Add the pieces to a food processor along with dried parsley flakes, granulated onion, granulated garlic, dried oregano leaves, and black pepper flakes.
Slowly pulse until the bread begins to break down into a uniform, fine consistency.
When your desired consistency is achieved, pour the breadcrumbs onto the baking sheet. Smooth to create a single layer.
Place into the oven for 5 minutes.
Remove and shake or rearrange as best as possible. Return to the oven for another 5 minutes.
Let cool and store in an airtight container for up to 1 month.