Preheat your oven to 180°C (350°F).
Cut your stale bread into pieces and toast it in a toaster until it is even drier and more crumbly.
Grind it into a powder using a mortar and pestle, but don't grind it too finely.You can also use a mixing bowl and a rolling pin.Set the powder aside in a bowl. In a mortar, grind the rosemary and thyme into a powder, then sprinkle it over the breadcrumbs.Add the garlic and onion, season with salt and pepper, and mix with a fork.Drizzle with olive oil and mix well until the ingredients are evenly coated in breadcrumbs. Bake at 180°C (350°F) for 20 to 30 minutes, stirring occasionally with a fork and checking regularly for doneness.
Remove from the oven, let the breadcrumbs cool to room temperature, then store them in an airtight glass jar for several days or weeks.
