Sweat and onion & stick of celery in a knob of butter or olive oil till softened (add a splash of white wine if you like). Add carrots (diced) and saute for 5 mins. Add approx 1 pint of vegetable stock, season & simmer for 20-30 minutes until carrots are cooked through. Leave to cool, then blitz in a blender until smooth. Return to a clean pan and reheat - stir in some single cream or creme fraiche/natural yoghurt.
You can add chopped coriander just before you blitz - or 1/2 inch fresh ginger root, grated for a different flavour.