1. Heat the olive oil in a large saucepan over medium heat. Add the leek and garlic, and cook until softened, about 5 minutes.
2. Add the Arborio rice and cook, stirring constantly, for 2-3 minutes until the rice is lightly toasted.
3. Pour in the white wine and cook until it has evaporated, about 2 minutes.
4. Begin adding the warm vegetable broth, one ladle at a time, stirring frequently. Wait until the liquid is mostly absorbed before adding more broth. Continue this process until the rice is creamy and cooked through, about 20 minutes.
5. About 5 minutes before the risotto is done, stir in the asparagus pieces.
6. Once the rice is cooked and the asparagus is tender, stir in the grated Parmesan cheese. Season with salt and pepper to taste.
7. Serve the risotto hot, garnished with extra Parmesan if desired.