
In a small saucepan, saute onion in oil until tender. Add garlic; cook 1 minute longer. Stir in flour until blended. Stir in the water, cream, bouillon and seasonings; bring to a boil. Reduce heat; cover and simmer for 5 minutes.
Cut shrimp into bite-sized pieces if desired; add shrimp to soup. Simmer 5-10 minutes longer or until shrimp turn pink. Place sour cream in a small bowl; gradually stir in ½ cup hot soup. Return all to the pan, stirring constantly. Heat through (do not boil). Top with cilantro and avocado if desired.