Creamy and filling, without the cream!
Preheat oven to 450 degrees F.
Cut up cauliflower into 2-inch pieces and place on a sheet pan. Toss together with 2 tablespoons of olive oil and season with salt and pepper. Roast for 20 minutes.
In a large soup pot, add 2 tablespoons of olive oil and heat over medium heat. Add the onion and sauté for 5 minutes. Add the garlic, celery salt, salt, and pepper and cook for 30 seconds. Add the vegetable broth, kale, and roasted cauliflower. Bring to a boil and reduce to a simmer for 15 minutes.
While the soup is simmering, place the bread cubes on a sheet pan. Toss well with 2 tablespoons of olive oil, and season with salt and pepper. Reduce oven to 350 degrees F and bake the bread cubes for 8 to 10 minutes, until crunchy.
When soup is finished, purée using an immersion blender or blender, being careful with the hot liquid. Serve croutons on top of soup.