Heat oil in a pot set over medium heat. Add onions and garlic and cook until softened, about 3-4 minutes. Add flour and mix until well-combined. Slowly stir in stock. Add potatoes and bay leaf and bring to a simmer until potatoes are very tender, about 20-25 minutes. Puree the mixture in a food processor or blender, and then return to soup pot. Stir in milk, green onions and dill, saving a little dill and onions to sprinkle on top, and heat through. Season to taste and pour into bowls. Sprinkle with chopped dill and green onions and serve.
Yields 5, 8oz servings.