Step 1

In a medium skillet, blanch the asparagus, whole, in boiling salted water for 2 minutes or until al dente. Remove the spears with a slotted spoon and shock in ice water. Reserve a half cup of the blanching liquid.

Step 2

Cut 2 inches from the tops and set aside. Thinly slice the bottoms and put them in the blender on low. Add just enough of the blanching water to loosen and start pureeing. Blend on high until smooth season with salt and pepper.

Step 3

In a small saucepan, heat the stock and maintain it at a slow simmer.

Step 4

Heat the olive oil in heavy large saucepan over moderate heat. Add onion and sauté until tender and translucent, about 4–5 minutes. Add the rice and stir 1 minute. Add wine and cook until absorbed, often stirring, 1–2 minutes. Add ½ cup of stock and simmer until the liquid is absorbed, stirring occasionally, 2–3 minutes. Continue in this manner, adding the hot stock a half a cup at a time until all of the stock has added and absorbed, and the rice is just tender and mixture is creamy, total cooking time 25 minutes. Stir in the Parmesan cheese.

Step 5

Now add the asparagus puree, reserved asparagus tips, lemon juice, and mascarpone, stirring gently to combine and heat through. Season to taste with salt and pepper, garnish with lemon zest, and serve with more Parmesan.