Season the cauliflower: Toss the cauliflower florets with the olive oil, herb seasoning, salt, and black pepper until evenly coated.
Roast: Add the cauliflower to the air fryer basket. Air fry at 400°F for 12–15 minutes, tossing halfway through, until the florets are tender with browned edges.
Blend: Set aside a few roasted florets for topping, if desired. Add the remaining cauliflower, broth, mascarpone or cream cheese, and lemon garlic butter sauce to a blender. I use the soup setting on my blender and blend until the soup is smooth and creamy.
Serve: Taste and adjust the seasoning. If you want a thinner soup, blend in a little more broth. Divide between bowls and top with the reserved roasted cauliflower.
Video
Notes
Use pre-cut cauliflower: Bagged florets make the prep especially quick. If you cut a whole head, keep the pieces similar in size so they roast evenly.
Use a salt-free seasoning: Since the recipe adds salt separately, a salt-free herb blend makes the seasoning easier to control.
Swap the broth: Vegetable broth works well if you want to make the soup vegetarian.
Soften cream cheese first: If you use cream cheese instead of mascarpone, letting it soften helps it blend more smoothly.
Adjust the consistency: Add extra broth a little at a time if you prefer a thinner soup.