1-2 tbsp butter
4 cups celery (including tops), chopped
1 medium onion, chopped
2 cubes chicken stock
4 tsp flour
2 cups skim milk
fresh ground pepper
1) In a large soup pot, saute celery and onion in butter on medium-high heat for 5 min. Add chicken stock and mix in. Cover and let simmer, stirring every few min, until celery is soft.
2) Uncover and sprinkle with flour. Stir until liquid is creamy. Remove from heat.
3) Transfer mix to a blender or food processor (I split it in two batches) and puree. If necessary, add some of the milk to aid with blending.
4) Transfer puree back to the pot and add the remaining milk. Add lots of fresh ground pepper (to taste). Simmer on medium-low until at desired thickness.
5) Serve warm or cold.