Prepping the Bread: Arrange gluten-free bread slices on a wire rack set over a baking sheet. Let them air dry in a cool, dry place for at least 8 hours or overnight. If you live in a humid climate, you can speed up the process by placing your slices near a dehumidifier. For a quicker option, preheat your oven to 300°F (150°C). Spread the bread slices on a baking sheet and bake for 15-20 minutes, flipping them halfway through, until completely dry and golden brown. Watch closely to avoid burning.

Processing the Breadcrumbs: For a smooth and even crumb, pulse the dried bread slices in a food processor in short bursts until you achieve your desired consistency. It's easier to grind finer than to course-correct larger pieces. If you're making a small batch or enjoy a more rustic texture, crush the dried bread slices in batches with a mortar and pestle until you get your perfect crumb.

Toasting the Breadcrumbs: Preheat your oven to 300°F (150°C). Spread the processed breadcrumbs on a rimmed baking sheet. Drizzle the breadcrumbs with a touch of olive oil and season with salt and pepper. Bake the breadcrumbs in the preheated oven for 10-15 minutes, stirring occasionally, until golden brown and fragrant. Keep a close eye to avoid burning. Cool the breadcrumbs completely before storing them in an airtight container at room temperature.