Melt your butter in a medium stock pot and add onion, celery, carrot, garlic. Over medium high heat, stir veggies every 2 minutes while keeping pot covered until they soften, about 6 minutes. Covering the pot in between stirs helps to steam the veggies, thus quickening their cooking time.
Add your brocc, stir, cover once more and cook 2 minutes, until it has turned bright green. Add stock, potatoes, scallions, parsley, pepper, mustard and lemon juice, and simmer soup for 10-12 minutes, until potatoes are very soft. Remove from heat.
Use an immersion blender to carefully blend your soup to the desired consistency - I went for pretty well-blended with some large chunks for kicks. Return to the heat and add your cream, cheddar, and goat cheese. Stir well and let it all melt and blend. Taste for salt and add, if needed.
Sprinkle any remaining cheddar over the top along with parsley or scallions, and serve. If you want a little heat, try the Jalapeno Oil on it. Nom.