Heat the oil in a large saucepan over medium heat. Add the onion and cook for 4 minutes.
Add the rice and cook, stirring constantly, for 2 minutes.
Add the wine and cook, stirring frequently, until the liquid is absorbed.
Stir in the broth, ¾ cup at a time (waiting until each addition of broth is absorbed before adding the next), and cook, stirring occasionally. It should take about 25 minutes for all the broth to be absorbed.
Remove from heat and stir in the edamame, lemon zest, tarragon, ¾ cup of the Parmesan, ½ teaspoon salt, and ¼ teaspoon pepper.
Spoon into individual bowls and top with the remaining Parmesan.