1 onion, finely chopped
150g potatoes, peeled and cut into small chunks
600g carrots, peeled (optional), and chopped into quarters
Salt and pepper
2 pints chicken or vegetable stock
Melt the butter. Add the onions and sweat for about 10 minutes. Add the chopped potatoes and carrots. Add the stock and simmer until the vegetables are soft. I like to leave them in a low heat oven for an hour or two but if you're making this in a rush then boil until the vegetables are soft.
Pour the soup onto a liquidiser and purée until smooth. Taste for seasoning and serve hot with crusty bread.
To garnish you can add a few sprigs of fresh mint.