Preheat the oven to 375°F (190°C).
Line a baking sheet with parchment paper or lightly grease it.
Place the bread cubes in a large mixing bowl.
Add the olive oil, minced garlic, Italian seasoning, garlic powder, onion powder, salt, pepper, and Parmesan cheese (if using).
Toss well until every bread cube is evenly coated.
Spread the bread cubes into a single layer on the prepared baking sheet.
Bake for 18–20 minutes, stirring halfway through, until golden brown and crisp.
Remove from the oven and let the croutons rest for 5 minutes to finish crisping as they cool.
Sprinkle with fresh parsley if desired.
Cool completely before storing in an airtight container.