Instructions

1. Bring 12 cups of water to a boil in a medium pot over high heat. Meanwhile, trim about 1⁄2'' from the ends of the asparagus. Lay spears on a work surface, then peel thin skin from each with a sharp swivel-blade vegetable peeler, starting 1 1⁄2'' from the top and running the length of the spear. (Spears are brittle and can snap when peeled in midair.) Reserve peels. Gather spears into 2 bundles and tie loosely with kitchen string.
2. When water in pot comes to a boil, reduce heat to medium. Add the reserved peels, sugar, 2 generous pinches of salt, 3 tbsp. of the butter, and 3 tbsp. of the lemon juice. Return to a simmer, then add asparagus and cook until tender when pierced with the tip of a knife, 8-30 minutes, depending on thickness of asparagus. Remove asparagus from pot and drain on paper towels, then set aside. Increase heat to medium-high and reduce stock by one-third, about 30 minutes. Strain stock and keep hot over low heat.
3. Melt the remaining 9 tbsp. butter in a large saucepan over medium-low heat. Add flour and cook, stirring with a wooden spoon, for 2 minutes. Do not allow flour to brown (it will color soup). Whisk in hot asparagus stock 1 cup at a time and continue whisking until smooth. Simmer soup, stirring often, until thickened, about 15 minutes. Add cream and continue simmering for 2 minutes more. Season to taste with salt and a little more lemon juice, if you like.
4. Untie asparagus bundles, then cut spears into 1'' lengths and add to soup. Simmer for 1 minute more. Adjust seasonings. Ladle soup into warmed bowls and garnish with spicy cress, if you like.