Cut the bread of your choice into half-inch cubes.
Spread the cubed bread on top of two cooling racks set in two half-sheet pans.
Heat your oven to the lowest setting (typically 150°–200°F) and bake for 45 minutes to an hour, or until completely dry.
If your oven only goes down to 250°, start by baking for 30 minutes, then check the dryness of a cube or two.
If using an air fryer, fill the basket to the max fill line, set to 300°, and air-fry for five minutes, then toss and air-fry for an additional three to five minutes until completely dry.
If using a food dehydrator, spread the cubed bread evenly over the racks, set to 150°, and let dry for an hour.
