2 tablespoons olive oil
3 shallot, finely chopped
3 sprigs fresh thyme
2 cups Arborio rice
3/4 cup dry white wine
1 1/2 pounds thin asparagus, woody ends removed, stalks cut into 1 1/2-inch lengths
4 tablespoons (1/2 stick) butter, cut into small pieces
1/2 cup grated Parmigiano-Reggiano cheese
1/3 cup mascarpone cheese
2 tablespoons finely chopped fresh mint leaves
Juice of 1/2 lemon
Sea salt and freshly ground black pepper
Parmigiano-Reggiano cheese, shaved with a vegetable peeler, for garnish
Bring the vegetable stock to a simmer in a large sauce pan. Reduce the heat to very low and keep the stock on the heat.
Heat the oil on a large heavy saucepan over medium heat. Add the shallots, garlic, and thyme, and saut for 2 minutes, or until the shallots are tender but not browned. Add the rice and saut for 30 seconds to coat with oil. Stir in the white wine and cook for 3 minutes, or until it is absorbed. Add the cup of vegetable stock and cook, stirring constantly, until it has been absorbed. Continue adding stock cup at a time, stirring until each addition has been absorbed, for about 22 minutes, or until the rice is al dente (the center of each grain of rice should still be slightly firm).
Add the asparagus and continue to cook for 2 minutes. Discard the thyme stems (the thyme leaves should have fallen off and into the risotto). Remove the risotto from the heat, and add the butter, grates Parmigiano-Reggiano, and the mascarpone cheese. Stir until the butter has melted. Then stir in the parsley, mint, and lemon juice and season the risotto generously with salt and pepper.
Divide the risotto among 4 warmed serving bowls. Garnish with the shaved Parmigiano-Reggiano, and serve.