Mario Batali shares a recipe for fresh asparagus and ricotta ravioli.
Bring 12 cups water to a boil in a large saucepan; add 1 tablespoon salt and return to a boil. Prepare an ice-water bath and set aside. Add asparagus to boiling water and cook until very tender, about 3 minutes. Drain and immediately transfer to ice-water bath to cool. Drain and pat dry.
Thinly slice asparagus on the bias. Measure out 1/4 cup and set aside for garnish. Place remaining asparagus in a large bowl along with ricotta, Parmigiano-Reggiano, and olive oil; season with salt and pepper. Set filling aside.
Set the rollers of a hand-cranked or electric pasta machine at their widest opening. Cut off a piece of dough about the size of a large egg, and flatten it with the palms of your hands. Keep remaining dough wrapped in plastic. Dust the small piece of dough lightly with flour, and run it once through the machine. Fold the dough in half, pressing it down with your fingertips, and run through the machine again. Repeat this step four or five times, dusting lightly with flour if needed, until the dough is smooth and elastic.
Now change the rollers of the pasta machine to a decreasing setting, and roll out the dough once without folding. Keep rolling the sheet through the machine on decreasing settings until you have rolled it through the last (thinnest) setting. Keep pasta sheet covered; repeat process with remaining pieces of pasta.
Cut each sheet of pasta into 4-inch rectangles. Place a scant tablespoon of filling on one half of each rectangle; moisten fingers or a pastry brush with water and brush edges of rectangle. Fold dough like a book to enclose filling, pressing edges with your fingers to seal.
Bring 24 cups water to a boil in a large pot. Add 2 tablespoons salt and return to a boil.
Meanwhile, in a large skillet, heat butter over high heat until it is no longer foamy. Add reserved asparagus and ramps, if desired; remove from heat. Transfer ravioli to boiling water; cook until tender, about 3 minutes. Drain, reserving 3 tablespoons pasta cooking water. Transfer ravioli and pasta water to skillet with asparagus and heat over high heat for 1 minute, gently tossing to combine; season with salt and pepper. Divide evenly among 8 warmed serving bowls; top with freshly grated Parmigiano-Reggiano and serve.