2 tsp butter or margarine
1/4 c chopped onions
1 clove crushed garlic
1 Tbsp all purpose flour
1 1/2 tsp curry powder
1 1/2 c defatted chicken broth
6 oz sliced yellow summer squash
1 c nonfat buttermilk
1 Tbsp lemon juice
Melt the butter or margarine in a heavy 2-quart (or 3-quart) saucepan over medium heat. Add the onions and cook, stirring frequently, for 5 minutes, or until they are soft but not brown. Stir in the garlic, then the flour and curry powder.
Add the broth and cook the mixture, stirring constantly, until it comes to a simmer and is slightly thickened. Add the squash and reduce the heat to low. Continue cooking over low heat, stirring occasionally, for 15 minutes, or until the squash is tender.
Let the soup cool to room temperature, then puree it in a a blender, working in batches if necessary. Stir in the buttermilk and lemon juice. Chill the soup in a covered container for 2 hours or overnight. Serve it ice-cold in bowls or mugs.