Can add salt and black pepper if tolerated
Chop celery finely
Chop potato into small chunks (approx 1 cm)
Chop cucumber into large chunks (approx 2 cm)
Rip lettuce into small pieces
Heat oil in pan
Add celery and potato
Cook until potato starts to brown
Sweat in low heat for 10 mins
Add 500 ml water
Bring to boil
Cover and simmer for 20 mins
Smooth in blender
Lastly, reheat gently before serving.
Also, this soup can be served chilled.