In a large soup pot, add the olive oil and onion, sauce for 3-5 minutes.
Once they become translucent, add the mushrooms, sweet potato, broth, salt, pepper, ground mustard, and cauliflower mixture.
Bring to a boil and cook until the sweet potato becomes tender, about 10 minutes.
Using an immersion blender or carefully using a high speed blender, blend the mixture until smooth.
Stir in the chopped broccoli and parmesan and cook until broccoli is tender. About 5 more minutes.
Serve!