Meanwhile, melt the butter in a medium saucepan over medium to medium-high heat, and then whisk in the flour 1 minute. Whisk in the milk and season with salt, pepper and nutmeg. Cook until the sauce thickens enough to coat the back of a spoon.
For the cheesy croutons: Preheat the oven to 350 degrees F. Heat the butter and oil in a large skillet over medium to medium-high heat. Stir in the garlic 1 minute, and then add the bread and toast until golden, stirring occasionally. Transfer to baking sheet and dress with the cheese. Bake to set the cheese and further dry out the croutons, 10 to 12 minutes.
Remove the herb bundle and bay leaves from the soup and serve with the croutons.