Heat a large saucepan over medium heat; coat with cooking spray. Add onions; cook 1 minute or until tender. Add butter, stirring until butter melts. Add flour; cook 1 minute, stirring constantly. Gradually stir in tomatoes and next 6 ingredients. Cook 9 minutes or until slightly thickened, stirring occasionally.
Pour tomato mixture into a blender; process until smooth. Return tomato mixture to pan.
Stir in shrimp. Cook 3 minutes or until shrimp are done. Divide soup evenly into bowls and top each serving with sour cream. Sprinkle with cilantro.