In a sauce pan, combine broth, water, lemon zest, salt & pepper together.
Bring to a simmer in a large skillet over medium heat, and 2 tablespoons of EVOO, and sauté the onion with salt until translucent.
Add the rice and cook for about 3 to 4 minutes then add the wine and saffron. Keep ladling one cup of the broth mixture into the skillet until most of the broth is absorbed every few minutes. Stir continuously and slowly, while adding a cup of broth at a time.
Risotto should be finished when it’s al dente about 20 minutes or so.
Last step is adding the shrimp and peas with the leftover broth. Careful not to overcook the shrimp or they will be too chewy - just until they are pink.
Remove from heat and grate the cheese and add the butter and lemon juice.
If you’re not serving right away and the risotto absorbs much of the moisture (Arborio rice tends to do) just add more broth.