Add carrots and celery with sherry/wine (if using). Reduce heat, cover pan and sweat vegetables for 15-20 minutes, shaking pan now and again to prevent sticking.

Add stock to pan, bring to boil. Reduce heat, simmer for 15-20 mins until vegetables are tender.

Purée mixture (Stick blender, food processor...) until smooth. Return to a clean pan. Taste and season if necessary. Enjoy.