Whole grain bread crumbs: To make your own bread crumbs, toast whole grain bread (gluten-free, if desired) for 10-15 minutes in a 400 degree F oven, until dry and brown (use 1 slice to make about ¼ cup of crumbs). Remove and let cool slightly, then place in a blender or small food processor and process into crumbs.
If you don’t want to serve all of the burgers at once: prepare and cook them according to the directions and refrigerate in an airtight container up to 3 days. Reheat in the microwave or in a skillet and serve as directed.
Variation: Substitute 2 ¼ cups cooked brown rice for the farro. This version is gluten-free (provided that you use gluten-free oats, buns, bread crumbs, and other ingredients).