Heat broth in a saucepan over medium high heat. Bring to a simmer, cover, and reduce heat to low.
Sauté asparagus, sun-dried tomatoes and shallots in olive oil in large, heavy saucepan for 2-3 minutes. Add rice and stir well to coat with oil; sauté for about 1-2 minutes. Add broth to rice, ½ cup at a time, stirring until the rice has absorbed the broth. Keep at a simmer and stir farily constantly until the rice is tender, but still slightly firm, about 20-25 minutes.
Remove from heat and add lemon zest, fresh basil, cheese, watercress, and walnuts and gently fold in to incorporate. Serve warm.