Cut off the dark green parts of the leeks then slice the leeks in half lengthwise. Rinse the layers under cold water to remove any dirt. Slice thin and set aside about 1/4 cup (for a topping)

Heat a stock pot over medium high heat and add the butter or oil. Add the sliced leeks and sauté for 5-8 minutes stirring occasionally to prevent sticking. Add in the turnips and cook, stirring, for another 5 minutes. Add enough water to cover over all of the turnips. Cook for 25 minutes or until turnips are soft. Season with salt and pepper. Puree using an immersion blender or let cool then puree in a standing blender. Taste and add additional seasoning to your preference.

Serve warm with toasted bread, herb oil, chives, or crispy fried leeks.