Fry chopped onion in a bit of olive oil in a frying pan till soft.

Add garlic, sweet potato and dry mustard and fry for two to three minutes. Stirring occasionally.

Add chicken or veggie stock and cauliflower and bring to the boil.

Reduce heat and cover. Simmer for 15-20 minutes or until the vegetables are tender.

Remove from heat and add buttermilk and puree.

Return soup to heat and add the grated cheddar cheese and heat it through approximately 2-3 minutes.

Season with salt and pepper and serve with crusty bread for dipping.