Peel, core and cut pumpkin into cubes.
Peel and cut onion, garlic, ginger, potato and carrots as well.
Heat up butter in a huge pot and sautée onion and garlic for 5 minutes. Add ginger and heat it up for 1 minute.
Add pumpkin, potato and carrot cubes and roast for about 5 more minutes.
Pour in vegetable broth, bring to the boil and let it cook for about 20 minutes, until soft.
Finally, add coconut milk and lemon juice. Purée everything with a blender until smooth and creamy and add curry powder to taste.
Serve the soup with roasted mushrooms, pumpkin seeds, chili flakes and fresh parsley as desired.