In a 6 quart pot, heat olive oil over medium heat. Add onion, leeks, garlic, celery, salt and pepper; sauté until onions are tender (7-10 minutes).
Add prepared vegetable stock and potatoes to sautéed vegetables. Bring to a boil. Reduce heat to medium and continue to cook until potatoes are soft (15-20 minutes).
Remove from heat and transfer ½ the liquid to a heat proof blender (don’t fill blender more than half way). Cover blender with lid and hold lid with a tea towel (contents are extremely hot- may need to vent lid). Pulse the blender to start and then puree until smooth (you may need to do this in two batches). Transfer pureed liquid back to pot with remainder of soup.
Return soup to stove top over medium heat. Add carrots and green onions to soup and continue cooking over medium heat until carrots are soft (10-15 minutes).
Serve warm with your favourite bread.
Yields 6-8 portions