In a heavy-bottom pot such as a Dutch-oven, add 1 tablespoon of olive oil and heat up over medium-high heat. Brown the shrimp on both sides without fully cooking them through, about 1 minute per side. Remove and set aside on a plate.
In the same pot, add the remaining tablespoon olive oil, then add the onions and garlic. Saute for 5 minutes, then add the risotto and cook, stirring gently, to toast it. Add the lemon zest and juice and turn the heat to medium; add the white wine. Continue stirring until most of the wine has cooked off, 5 to 7 minutes. Slowly add about 1/2 cup of chicken broth, and cook, stirring frequently, until the liquid has been absorbed; then add another 1/2 cup chicken broth. Continue doing so in this manner until the risotto is fully cooked through and the liquid has been completely absorbed. (You may need more or less than the 3 1/2 cups of chicken broth.)
Season with salt and pepper to taste, then add the shrimp back in. Toss to incorporate and cook until the shrimp are cooked all the way through, 2 to 3 minutes. Divide evenly into 2 bowls and serve!