Cut the protein bread into small cubes (about ½").
Pour the olive oil into a large ziplock bag (and zip it closed), and move the bag so the oil gets all around the bag.
Add the protein bread cubes (and zip it closed), and toss the bag around so the cubes get tossed in the olive oil.
Mix the salt, powders, and herbs in a small bowl, then add to the ziplock bag. Zip the bag closed and toss again, until the bread cubes are covered with the mixture.
Pour bread cubes into a foil-lined baking pan (mine was 13x9x2 inches).
Bake at 300F (150C) for 30 minutes, stirring the croutons in the pan after 15 minutes.
Let cool, and enjoy!
Store in the same ziplock bag, in the refrigerator.
Notes
Because this bread is a little more dense than traditional bread, the croutons come out better when they are small. Also, I would imagine these would stay fresh for about a week in the fridge, but I usually eat mine all before the week is up!