Lay the bread slices on a cookie sheet and put in the oven for 35 min. Flip the bread slices over and return to the oven for another 35 min. At the end of the second cooking cycle, if the bread is not completely dry and very hard, return to the oven for another 15-20 min. See Note at bottom for alternative methods.
Break the bread up into chunks and put in the bowl of the food processor. Run the food processor until you have mostly fine bread crumbs.
Add the garlic powder and black pepper to the food processor and give it a few whirls to mix in the spices.
Add the dried parsley to the food processor and give the food processor a few whirls to finely chop the parsley. Do NOT use fresh parsley as it will add moisture to the mix. See note at bottom.
Measure the bread crumbs as you add them to an air tight container. I get ½ c of crumbs from the brand of bread I use but you may get more or less depending on the brand of bread you use.
They store well at room temperature for several weeks. I make them as I use them.
Notes
You can leave the slices of bread out on your countertop for several days and let it dry out until it is hard.If you have a gas oven with a pilot light, you can put the bread slices on a cookie sheet and leave it in the oven until it dries out and is hard.If you prefer fresh parsley, then leave it out of the recipe and add it to the bread crumbs just before using them.