1. Melt the butter in a skillet. Add onion and fry till softened.
2. Add potato, avocado, mint and 4 cups of water or stock.
3. Simmer till the vegetables are cooked.
4. Cool and blend till smooth.
5. Combine mushrooms with remaining water or stock. Simmer for 2-3 minutes.
6. Add the blended mixture, salt, pepper and milk.
7. Heat thoroughly and serve garnished with cream.

Serves: 6 to 8