Preheat the oven to 350 degrees. Melt the butter In a microwave safe bowl. Stir in the garlic salt and onion powder.
Place the bread cubes in a large mixing bowl. Drizzle with the butter mixture and toss to coat.
Spread the buttered bread cubes out on a 11 x 17 baking pan. Bake for 5 minutes. Stir the croutons and bake 7 minutes, or until golden and crispy. Store in an airtight container.