Set the oven rack in the middle position, then preheat the oven to 300℉.
Cut the bread slices into 1-inch cubes then place them in a large mixing bowl.
In a small bowl, combine the chopped parsley, melted butter, and garlic powder.
Pour the butter mixture over the cubed bread then quickly toss to combine.
Spread the seasoned bread cubes into a single layer on a baking sheet, then bake them for 25-30 minutes, or until they are golden brown, firm, and crispy.
Once the croutons have cooled to room temperature, transfer them to an airtight container for storage or use immediately.