Preheat your oven to 250°F (120°C). Tear or cut the stale bread into small pieces and spread them evenly on a baking sheet. Bake for 15 - 20 minutes or until the bread is dehydrated and crisp. Allow the bread to cool completely.

Once the bread is cooled, pulse it in a food processor until you achieve the desired crumb size. For finer crumbs, pulse longer. For coarser crumbs, pulse less.

Heat 2 tablespoons olive oil in a large skillet over medium heat. Add 4 cups breadcrumbs to the skillet and stir to coat them evenly with the oil. Toast the breadcrumbs, stirring frequently, until they turn golden brown and crispy, about 5 - 7 minutes.

Remove the skillet from the heat and stir in 2 tablespoons fresh parsley (or 1 tablespoon dried parsley), 1 teaspoon dried oregano, 1 teaspoon garlic powder, ½ teaspoon kosher salt, and ¼ teaspoon ground black pepper. If using, add ¼ cup grated Parmesan cheese and ¼ teaspoon red pepper flakes. Mix well to combine.

Allow the breadcrumbs to cool completely. Store them in an airtight container at room temperature for up to 2 weeks. For longer storage, keep them in the refrigerator for up to a month or freeze them for up to 3 months.