Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper. Cut the bread into evenly sized cubes, about ½ to 1 inch in size.
In a large bowl, drizzle the bread cubes with olive oil. Sprinkle with garlic powder, herbs, salt, pepper, and chili flakes (optional). Toss until evenly coated.
Arrange the cubes in a single layer to ensure even crisping.
Bake for 20 minutes, flipping halfway through, until golden brown and crispy.
Cool completely before storing in an airtight container.