Place a large saucepot over medium heat.
Add the butter, olive oil, and stir. Once the butter has melted add onions and leeks. Sauté for 3-4 minutes until soft.
Add garlic, some salt, pepper, and the dried parsley. Stir to combine. Cook for 2-3 minutes.
Add the beer, deglaze the pot.
Next, add the cauliflower florets, potatoes, broth, and some salt and pepper. Bring to a boil, then lower the heat a little and simmer for 20 minutes, or until the cauliflower and potatoes are fork-tender.
Using an immersion blender, puree the soup until smooth, with just a few chunks. Then add the shredded cheese and blend in until combined.
Stir in the fresh dill, and taste for salt and pepper.
Serve warm garnished with more cheese and chopped green onions or dill.