Heat oven to 425°F. Line a large baking sheet with parchment.
Toss cauliflower with about half the oil, a pinch of salt, and pepper. Spread in an even layer.
Roast until edges are deep golden and tender, 25–30 minutes, flipping once halfway.
Warm remaining oil and the butter in a soup pot over medium heat.
Soften onion for 5–6 minutes. Stir in garlic, thyme, and smoked paprika; cook 1 minute until fragrant.
Pour in the broth and bring to a gentle simmer, scraping up any browned bits.
Add roasted cauliflower. Simmer 8–10 minutes to meld flavors.
Blend until smooth with an immersion blender. Thin with a splash of broth if you like.
Stir in cream and lemon juice. Season with remaining salt and more pepper to taste.
Ladle into bowls and finish with chives.
Notes
Make it dairy-free: swap the cream and butter for full-fat coconut milk and a bit more olive oil. For a flavor twist, add 1–2 tsp mild curry powder with the garlic. Leftovers keep 4 days in the fridge or freeze up to 2 months; rewarm gently and add a splash of broth if thick.This recipe is an original creation inspired by classic Easy Roasted Cauliflower Soup flavors. All ingredient ratios and instructions are independently developed.