Toss the cauliflower florets with 2 tbsp olive oil, salt and pepper.
Spread the florets in a single layer on a baking sheet lined with parchment paper.
Roast in the oven for 20-30 minutes until the florets are golden brown. In the meantime, continue on to the following steps.
In a large non-stick pot, heat 1 tbsp oil on medium heat. Add the garlic and fry for a few seconds until fragrant.
Immediately add the mushrooms and thyme and saute on medium heat until the water released from the mushrooms is mostly evaporated and the mushrooms themselves are tender.
Add the green onions and cook for an additional 5 minutes, mixing frequently.
Add the white wine and cook until the liquid reduces to about half the volume, mixing frequently.
Add the roasted cauliflower and vegetable broth and bring to a boil. Once boiling, reduce the heat and simmer for about 30 minutes, covered.
Season with salt and pepper to taste.
Using a stick immersion hand blender , puree soup in brief pulses until you reach the desired thickness and chunkiness. Note that some of the mushrooms and cauliflower in the soup should be in pieces so that the soup is "chunky" in nature and not completely smooth.
If using, add the non-diary milk and vegan parmasan cheese and simmer on medium heat for about an additional 10 minutes.
Season to taste with salt and freshly ground black pepper.
Serve the soup hot with a side of your favorite bread.
Notes
Vegetable Broth - I use Imagine Brand Low-Sodium Organic Vegetable Broth in most of my recipes and soups.Non-Dairy Milk - If you prefer a creamy soup, use a neutral flavor unsweetened non-dairy milk such as cashew milk or almond milk. You can also opt to omit the non-dairy milk completely and the soup will still taste great, just thicker (I've tried both variations).Vegan Parmesan - I prefer using Follow Your Heart brand or Violife brand.