Step 1 - In a large pot saute the onion and celery in the oil until tender
Step 2 - Add the remaining ingredients except the Avocado and bring to a boil
Step 3 - Reduce the head and simmer until the vegetables are tender
Step 4 - Using an immersion blender or Ninja Blender puree the mixture until smooth being very careful of the hot liquid and do small amounts at a time
Step 5 - Add the Avocado and puree until smooth. Serve with croutons or Grilled Cheese Sandwiches! Enjoy!