Melt the butter and olive oil in a medium pot. Add the onion and garlic and cook for about 3 minutes, stirring occasionally. Add the carrots and cauliflower florets. Stir well with a wooden spoon.
Add the broth to the pot and bring to a boil, then reduce the heat to medium-low. Add the cumin, bay leaf and season with salt and pepper. Cover and cook for about 25 minutes.
Remove the pan from the heat, discard the bay leaf and add the cheese. Stir well with a wooden spoon. Transfer the soup to a blender or using an immersion blender, blend the soup until smooth. Return the soup to the pot and add the cream. Stir and simmer for 5 minutes, season with salt and pepper and divide into serving bowls. Sprinkle red pepper flakes. Serve warm.