Preheat oven. Adjust oven rack to center position and preheat oven to 375 degrees Line a large, rimmed baking sheet with parchment paper.
Cube or tear bread. Either cut bread into ¾ inch-cubes with a knife or tear bread into small chunks by hand. Make sure the croutons are uniform in size so they bake evenly.
Toss with oil and seasonings. Place cubed bread in a large bowl. Drizzle bread with oil. Toss to coat. Sprinkle with parmesan, garlic, seasoning, ½ teaspoon kosher salt and ¼ teaspoon black pepper. Gently toss to evenly coat.
Spread croutons out on a rimmed baking sheet. Transfer the bread cubes onto the prepared baking sheet. Make sure the croutons are spread out in a single, even layer.
Bake. Bake the croutons, tossing once halfway through baking, for 15-20 minutes, or until the croutons are golden brown and crispy. Remove from oven and season with salt and more parmesan if desired. Allow the croutons to cool slightly on the pan. Use immediately, or allow transfer to a plate and allow to cool completely before storing in a zip-closure bag.