Heat 2 tablespoons olive oil in a large skillet over medium heat.
Add the chopped onion and cook for 3-4 minutes until softened.
Add the minced garlic and crushed red pepper flakes; cook for 1 minute until fragrant.
Add the orzo pasta to the skillet and stir to coat it with the oil, onion, and garlic mixture.
Pour in the chicken broth and water, then add lemon zest and a pinch of salt and pepper.
Bring the mixture to a boil, then reduce heat to low, cover, and simmer for 10 minutes or until the orzo is tender and most of the liquid is absorbed.
While the orzo cooks, heat the remaining 1 tablespoon olive oil in a separate pan over medium-high heat.
Add the shrimp, season with salt and pepper, and cook for 2-3 minutes per side until pink and opaque. Remove from heat.
Once the orzo is cooked, stir in the lemon juice and butter until the butter is melted and the mixture is creamy.
Add the cooked shrimp to the skillet and gently fold to combine.
Sprinkle with chopped fresh parsley before serving.