Using your oven or toaster oven, toast sourdough until it is completely dried out. I usually do this in a 350 degree F oven for 20-30 minutes, occasionally checking to see if it is completely dried out.
When your bread is completely dried out, add it in chunks to a food processor. Make sure the food processor and the bread are completely dried out by breaking the pieces in half and checking for moisture
Blitz bread in the food processor until small crumbs are formed. The breadcrumbs do not need to all be the same size, but you can blitz until they are uniform.
Store in the freezer until ready to use.
