Preheat an oven to 400°F.
In a 3 1/2-quart wide Dutch oven over medium heat, warm 2 Tbs. of the olive oil. Add the leeks and cook, stirring occasionally, until soft, about 8 minutes. Add the garlic, thyme and salt and cook for 1 minute. Add the rice and cook, stirring occasionally, until lightly toasted, 2 to 3 minutes. Add the wine and cook for 1 minute. Stir in 3 cups of the broth, increase the heat to medium-high and bring to a simmer. Cover the pot, transfer to the oven and bake, stirring once halfway through, until the rice is tender and the liquid is absorbed, 25 to 30 minutes.
Coat the asparagus with the remaining 1 Tbs. olive oil and season with salt and pepper. Preheat a stovetop grill pan over medium-high heat. Working in batches, grill the asparagus, turning occasionally, until tender, 7 to 8 minutes per batch. Cut the asparagus on the bias into 2-inch lengths.
Stir the remaining 1 1/4 cups broth into the risotto, then stir in the cheese, butter, asparagus, salt and pepper. Spoon the risotto into warmed bowls and serve immediately. Serves 4 to 6.
Recipe courtesy of Williams-Sonoma