Preheat your oven to 400ºF and line a baking sheet with parchment paper. Set aside.
If you haven't already, cut your sourdough bread into ½-1" cubes.
Add the olive oil, garlic, salt, dried parsley, and black pepper to a very large bowl. Whisk to combine.
Add the cubed dried bread cubes and toss them until they are lightly coated with oil.
Spread the sourdough bread cubes out onto the prepared baking sheet in a single layer.
Bake until browned, 12-18 minutes (mine were done at 15), tossing halfway through baking to ensure even browning.
Allow your sourdough croutons to cool completely before transferring to an airtight storage container or ziploc bag.