4 Tbsp. butter
1 leek, trimmed, washed & chopped
2 garlic cloves, thinly sliced
1 lb. russet potatoes, peeled & diced
2 qt. water or vegetable stock
1 cup crème fraîche
1/2 lb. spinach
1/2 lb. stinging nettles
Salt & pepper, to taste
In a four-quart saucepan over medium heat, add butter, leek, garlic, and a little salt, and sweat until very soft. Add potatoes and water or vegetable stock and cook until potatoes are falling apart, about 15 minutes. Transfer to a blender or food processor and blend until smooth. Strain through a fine sieve. Return the blended potatoes to the pan over the lowest heat and add crème fraîche.
In a separate pot, blanch the spinach and nettles (remove any woody stems) in salted boiling water for two minutes until tender. Using the blender or food processor, blend the greens with a cup of blanching liquid until smooth. Pour through a fine sieve into the potato soup, and discard what remains in the sieve. Season with salt and pepper. Heat until hot and serve.