Preheat the oven to 300 degrees F.
In a large mixing bowl, add the cut pieces of bread (depending on the size of the bowl used, this may need to be made in two batches). Set aside.
In a microwavable small bowl add butter and 10 Rosemary leaves. Cover the bowl with a paper towel and warm at 25-second intervals until the butter is melted.
To the large bowl with the bread, drizzle butter (with the rosemary leaves) over the bread and gently mix together.
To the large bowl, add granulated garlic, dried parsley, and grated Parmesan cheese over the bread and gently mix together.
To a large sheet pan (with sides) add the pieces of bread, making sure that the pieces are spread out and laying evenly on the pan. On top of the bread drizzle olive oil.
Bake in preheated oven for 40 minutes. Occasionally move the croutons around using a spatula.
Then turn up the heat to 375 degrees F. for a few minutes. Just long enough so that the croutons get slightly browned.
Let cool before serving.