3 tablespoons unsalted butter
1 medium yellow onion, chopped
1 leek, well cleaned and finely chopped
1 rib celery, chopped
1/2 cup flour
8 cups chicken broth ( **or vegetable broth for vegetarian recipe)
1 1/4 pounds fresh, shelled English peas (or frozen bagged peas)
Coarse salt and freshly ground pepper
1 cup whole milk (with added 1/2 cup nonfat powdered milk for extra creaminess)
Melt butter in a large saucepan over medium heat. Add onion, leek, and celery, and cook until soft. Add flour and stir till combined. Slowly add broth while whisking to keep from making the soup lumpy; bring to a boil. Reduce heat and simmer, 10 to 15 minutes. Remove from heat.
Prepare an ice-water bath. Fill another large saucepan with water and bring to a boil over high heat. Add salt and return to a boil. Add peas and cook until tender, about 5 minutes- don't over cook. Drain and immediately transfer peas to ice-water bath to cool. Drain and add to saucepan with vegetables and stock.
Working in batches, puree the soup in a blender or food processor (Warning: Use the lid and cover with a towel before starting to keep from spraying hot liquid everywhere!!) Return to saucepan. Add milk and place saucepan over low heat. Season with salt, pepper, and sugar.