Boil Savoy cabbage in hot water for about 5 minutes (to remove bitterness). Drain.
Add water, buillion cube and thyme and cook until the cabbage is soft.
Remove from heat. Puree the soup using a hand held immersion blender (or regular blender). Add milk and lemon juice. Season with salt and pepper. Boil for one more minute.
Optional: Decorate with a sauteed Brussel sprout, few drops of olive oil and sprinkle with Parmesan cheese.