Quick Two Bean Soup

Heat butter in a large saucepan. Add onions and cook, stirring, until golden, about 8 minutes. Add green beans and garlic and stir 20 seconds. Add broth, water, cannelini beans, salt, pepper and cayenne. Heat to a boil. Cover and simmer 15 minutes. Working in batches, puree 3/4's of soup in a food processor. Return pureed soup to pan and stir in ginger and lemon peel. Heat soup to a simmer. Stir together sour cream and tabasco in a small bowl. Stir lemon juice into soup. Portion soup into bowls and garnish with dollops of sour cream.