PREP: Preheat the oven to 375°F (190°C). Cover a large baking sheet with parchment paper. Cut bread into ¾ inch (2 cm) cubes with a sharp bread knife.
MIX: Melt butter by microwaving it in 15 second increments, stirring in between, until melted. Combine melted butter, olive oil, garlic powder, salt, black pepper, sage, thyme, basil, rosemary, and oregano and mix well.
TOSS: Add cubed bread to a large bowl. Slowly drizzle the butter and herb mixture over the bread cubes a little at time, tossing in between, until all cubes are evenly coated. Stir butter and oil mixture to keep herbs from settling.
SOAK: Let the bread cubes sit for about 5-10 minutes so they can fully absorb the butter and oil.
BAKE: Pour bread cubes onto the prepared baking sheet in a single layer and spread out evenly. Bake for 10-15 minutes in the preheated oven until croutons are golden brown and crisp. You want them to be fully dried out with no soft spots, or they will get stale with storage.
SERVE: Cool slightly and use now, or allow to cool COMPLETELY before storing in an airtight container. It is very important for them to be 100% cool before storing or they can get stale faster.
Notes
Total cooking time depends on how dry the bread is to begin with. Fresher bread will need more time to dry out in the oven.
Use a sharp serrated knife so you don't squish the bread when you cut it.
If your bread is fresh, cube the bread and let it dry out for about 30 minutes on the counter if needed.
If your bread is stale, allow the butter and herb mixture to sit longer before baking so it has time to absorb into the stale bread. You can also add 1-2 tablespoons of water into the butter and oil mixture. Stir frequently while drizzling the mixture over the bread. The water will help the butter and oil absorb better into the stale bread.
Use a large sheet pan so the croutons can spread out and release moisture while baking. You can also use 2 smaller baking sheets.
How to store leftovers: Before storing, make sure croutons are COMPLETELY cooled. I usually let them sit at room temperature for at least an hour before storing. Store in an airtight container for up to 2 weeks. If using a zip-top bag, squeeze out excess air.
How to freeze: Cool completely and add to an airtight freezer safe container. Freeze for 2-3 months. Thaw at room temperature. Re-crisp them in the oven or in a pan over medium heat.