Yuba Pappardelle with English Peas, Fava Leaves, and Basil

Make pea purée:

In 10-inch sauté pan over moderately high heat, bring vegetable stock and salt to boil. Add peas and simmer, uncovered, until bright green and almost tender, 1 to 2 minutes.

Transfer peas and cooking liquid to blender and blend on high until very smooth, about 1 minute. Set aside. (Purée can be made ahead and refrigerated, tightly wrapped in plastic wrap, up to 12 hours. To maintain peas' vibrant green color, cool purée over ice bath before refrigerating.)

Make pappardelle:

In medium saucepan over moderate heat, stir together buttermilk, yuba, peas, and 1/4 teaspoon salt. Bring to simmer, then reduce heat to low, cover, and cook until peas are just tender, about 2 minutes. Stir in pea purée and fava leaves, cover, and cook until fava leaves are wilted, about 30 seconds. Remove from heat and stir in basil, remaining 1/4 teaspoon salt, and pepper. Serve immediately.