Notes: If you cannot find crème fraîche, substitute sour cream; omit lemon juice and add 1 more teaspoon lemon peel.
Rinse peas in pods. Cut off and discard tough ends from pods; pull off and discard strings. Shell peas. Reserve pods; blanch and reserve peas. To blanch fresh peas, bring water to a boil in a large pan, then add peas. Cook just until they start to turn a brighter green, 15 to 30 seconds, then drain immediately. Rinse well under cold running water until cool, then drain again.
In a 4- to 5-quart pan over medium heat, melt butter. When it is foamy, add shallots and stir until limp, about 3 minutes. Add wine, increase heat, and boil, stirring, until about half the liquid has evaporated. Add pea pods, chicken broth, and 3 cups water; lower heat, cover, and simmer for 20 minutes. Add rice and cook until pods are tender when pierced, 25 minutes longer.
In a small bowl, stir together crème fraîche, lemon peel, and lemon juice.
Working in small batches, transfer pod mixture to a blender; whirl until nearly smooth. (The tough bits of pea pods may catch on blade; stop motor and remove blender jar to clean blade as needed.) Pour soup through a fine strainer into a 4- to 5-quart pan, pressing on solids to extract liquid; discard solids.
Stir in half the lemon crème fraîche; add salt and pepper to taste. Set over medium heat; stir occasionally until soup is steaming. Add blanched peas. Ladle soup into bowls and top each with lemon crème fraîche.