1large yukon gold potatopeeled and cut into small dice
lemon juiceto taste
zest of 1 small lemonorganic
Fill a pot with salted water and bring to a boil. Using a vegetable peeler, peel the lower half of the asparagus, exposing the tender part underneath. Cut off the bottom inch. Slice into 1 inch pieces, but keep 12 of the heads separate to use as garnish, about 2 inches long each. Blanche the asparagus in the simmering water for 1-2 minutes, until bright green and crisp-tender. Strain through a colander and into a large bowl, reserving the asparagus water. Rinse the asparagus under cool water to stop the cooking, and set aside.
Trim the root ends off of the green garlic and leeks. Slice the green garlic into thin rounds, including the green part if it's still nice and fresh. Slice the leeks in quarters lengthwise, then slice the white and light green parts crosswise into thin slices. Place the green garlic and leeks in a large salad spinner and fill with water. Swish them around, drain, and repeat three times. Once all the dirt is removed, spin to remove any remaining moisture.
Melt the butter and olive oil together in a soup pot or dutch oven over medium heat. Add the leeks and green garlic and a bit of salt, and sauté until bright green and tender, 5-10 minutes. Add the potato, a bit more salt, and enough of the reserved asparagus cooking water to cover the vegetables, 4-6 cups. Bring to a boil, then reduce to a simmer and cook until the potato is very tender, 10-15 minutes.
Meanwhile, stir together the crème fraîche and lemon zest in a small bowl. It's important for the lemon to be organic, since you are using the skin.
Add the asparagus to the soup pot, reserving the longer heads for garnish, and puree with an immersion blender, or in batches in a regular blender, thinning with more asparagus water as needed. Stir in the juice of half a lemon, taste and adjust seasoning if needed.
Serve in bowls with a dollop of crème fraîche and a couple of asparagus tips. The soup will keep in the fridge for up to 3 days, or frozen for 3 months.
This soup can be made vegan by omitting the crème fraîche garnish.