Wash and cut the potatoes.
In a Dutch oven over medium-low heat, add olive oil and butter, heat until the pan is hot.
Add onion, celery, and salt. Stir and cook partially covered for 8 minutes. Stirring occasionally.
Remove lid add garlic and cook for about 6 minutes, stir occasionally. Until the vegetables are soft.
Add remaining ingredients. Simmer until potatoes are tender. About 30 minutes.
Use an immersion blender to blend some of the potatoes to thicken the soup.
Garnish and serve.