Heat the oil in a nonstick skillet over medium-high heat.
Add the onion and carrot and cook, stirring frequently, until the vegetables
begin to brown, 8-10 minutes.
Place in a slow cooker with water, leek tops, celery, turnip, mushroom and seasonings.
Simmer on HIGH for 6 to 8 hours or overnight until vegetables are very soft.
Strain off stock and discard vegetables.
Yield: 8 servings
Variation: In place of leek tops, use a combination of two or more
of the following: loosely packed spinach stems and leaves, lettuce
leaves, tomato skins, fresh mushroom stems, or diced parsnips along
with some additional celery and carrot to equal 3 cups vegetables.