Make the croutons by pre-heating the oven to 375ºF (or pre-heat the air fryer to 370ºF). Toss the cubed bread in a bowl with the olive oil and season with salt and freshly ground black pepper. Spread the cubes out on a baking sheet and toast in the oven for 10 to 15 minutes or until nicely toasted (or air-fry for 5 minutes).