Preheat the oven to 350 °F. Cut bread into cubes and place in a large bowl.
In a small microwave-safe bowl, melt the butter and combine with the salt, garlic powder and pepper. Pour over the bread cubes and toss or stir to evenly coat.
Spread in a single layer on a baking sheet (ensure there is space between the croutons and they are not over crowded) and bake for 10 minutes.
Remove from oven and stir/flip. Bake for an additional 5-10 minutes, keeping a close eye on them, until lightly golden brown.
Remove from the oven and allow to cool completely before using.
Notes
LeftoversCool completely and store leftovers in an airtight bag at room temperature for up to 4 days or freeze for up to 3 months.