Preheat oven to 350°F. In a large bowl, toss cubed bread with oil and butter until evenly coated. Add in salt, pepper, garlic powder, onion powder, rosemary, and Parmesan, and toss to combine until evenly distributed.
Divide seasoned bread between two large baking sheets.
Bake until golden and crispy, flipping halfway through, about 15 minutes total.
Notes
Nutritional information is only for the homemade croutons.