Healthy whole-grain bread crumbs are often hard to find as they can have hydrogenated oils, high fructuse corn syrup, and other undesirable ingredients in them. It is very easy to make your own and you can leave them plain or cube them for croutons and season them any way you desire.
I really like making them out of my whole-wheat French bread recipe, but if you are not a baker it is very simple to make them from whatever healthy bread you normally eat. I don’t personally care for breads with seeds or nuts for drying breads as they get very hard.
Here is how I make both crumbs and croutons.
Be sure you have day-old bread or bread that is substantial enough to cut or process. You can remove the crusts if you prefer, this is not a step I take.
For cubes: Stack your bread slices four or five together and cut into half inch cubes or whatever size you prefer. They will shrink so take that into consideration. Then lay them out one layer deep on a cookie sheet. Season or leave plain. If seasoning, sprinkle lightly with your choice herbs. I use sage or Italian Seasoning (crumbled), onion granules, garlic granules, and celery salt. The reason I use celery salt is because it is difficult to get a light sprinkling of ground celery seed. You want to be really careful with the garlic also. Lastly, mist them with water, careful not to get them too wet, but this will hold on the spices without using oil.
For crumbs: I find it is much easier and less messy to make crumbs out of them before drying them. Take a large blender or food processor, tear several slices of bread into fourths, and process until they are crumbs, making them as fine as you would like. Lay them out on a cookie sheet (I like to use parchment so they don’t burn as easily or stick). Spread them evenly and not too thick.
Bake at 250 degrees convection (preferable) or 275 conventional. Check after 20 minutes and then every 10 minutes after that to be sure they do not burn. Stir the crumbs several times, not necessary with the cubes.