01 - Pat the shrimp dry with paper towels and season generously with salt and freshly ground black pepper.
02 - Heat 1 tablespoon of butter in a large sauté pan over medium-high heat. Arrange the shrimp in a single layer and cook for 1 to 2 minutes per side until they turn pink and are just cooked through. Transfer the shrimp to a plate and set aside.
03 - Add the remaining butter to the same pan. Sauté the chopped onion for 2 to 3 minutes until translucent. Stir in the minced garlic and cook for 30 seconds until fragrant.
04 - Add the orzo to the pan and toast for 1 to 2 minutes, stirring constantly. Pour in the white wine and let it evaporate, stirring occasionally.
05 - Add the broth, half a cup at a time, stirring frequently and allowing the orzo to absorb the liquid before adding more. Continue this process until the orzo is just tender and the mixture is creamy, about 10 to 12 minutes.
06 - Stir in the heavy cream and Parmesan cheese until smooth and well combined. Fold in the baby spinach and cook until wilted, about 1 minute.
07 - Return the shrimp to the pan. Add the lemon zest, lemon juice, chopped parsley, and red pepper flakes. Gently stir everything together until heated through. Taste and adjust the seasoning with salt and pepper as needed.
08 - Serve hot, garnished with extra parsley and lemon wedges if desired.