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Make sure that all the ingredients are well combined. Bake them for 12 to 15 minutes, depending on the desirable crispiness you wish.
Preheat your oven to 375°F (190°C) and spray a flat baking sheet with nonstick cooking spray. Toss the bread cubes, olive oil, garlic and rosemary in a large bowl, using either a spoon or clean hands. Spread the cubes onto the baking sheet. Remove the croutons from the oven and set the baking sheet on your range top so the croutons can cool.