Preheat oven to 425 degrees.

Cut the top of the head of garlic (about 1/2 inch). Place the garlic head onto a piece of aluminum foil, drizzle with olive oil, and season with salt and pepper. Cover completely with aluminum foil and bake for about 40 minutes to an hour. When cooked, let cool and then squeeze out the cloves.

Melt the butter in a large heavy pot, preferably a dutch oven. Add the onions and shallots and on medium heat, cook until translucent (about 10 minutes), stirring occasionally.

Add the tomato paste and stir frequently for 5-7 minutes. Add roasted garlic cloves to the pot and stir for 1-2 minutes. Add the tomatoes and chicken broth and bring to a boil then simmer for 10-15 minutes.

Stir in the celery salt, fresh basil, thyme, and nutmeg. Season with salt and pepper. Let simmer for another 10 minutes. Taste and add more salt and/or pepper if needed.

In small batches, transfer the soup to a blender or food processor and blend until a smooth texture is achieved. Once all the soup is blended, transfer it back into the pot and add the heavy cream. Keep the soup on low heat while you make the cheesy croutons!

Turn broiler on high (or if you don't have one, preheat oven to 425 F).

Sprinkle cheese on baguette slices. Place on a baking sheet and watch carefully until the cheese is fully belted and the edges start to slightly brown, about 3-5 minutes.