Place a large pot over medium heat. Add the olive oil and butter. Cook onions until translucent for about 5 minutes. Add the garlic and cook for 30 more seconds until fragrant.
Add cauliflower florets, broth, smoked paprika, cayenne pepper, and fresh thyme sprigs. Cover with a lid and bring the soup to a boil. Simmer for 15-20 minutes or until the cauliflower is fork tender. Remove the thyme sprigs.
Blend using an immersion blender to puree until super smooth.
Stir in cream, and season with more salt and pepper to taste. Reheat if needed.
Garnish with a drizzle of olive oil, fresh thyme, and lemon juice.