Season and sear the shrimp: Pat the shrimp dry and season with salt, pepper, and half of the Italian seasoning. Heat olive oil and butter in a large skillet over medium-high heat. Sear the shrimp for 1–2 minutes per side until just pink. Transfer to a plate and set aside.
Sauté onion, garlic, and sun-dried tomatoes: In the same skillet, lower the heat to medium. Add the diced onion and cook until softened. Stir in the garlic and chopped sun-dried tomatoes and sauté for 30 seconds, until fragrant.
Toast the orzo: Add the orzo to the pan and stir to coat it in the oil and aromatics. Toast for about 1 minute, stirring constantly so it doesn’t stick.
Add broth and seasonings: Pour in the chicken broth. Add the remaining Italian seasoning, dried oregano, chili flakes (if using), a pinch of salt, and black pepper. Stir well, bring to a gentle simmer, and cook for 8–10 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Make it creamy and add shrimp back: Lower the heat. Stir in the heavy cream and grated Parmesan until the sauce becomes creamy and smooth. Add the spinach and cook just until wilted, then return the seared shrimp to the pan. Simmer for 1–2 minutes so everything warms through.
Finish and serve: Turn off the heat and let the creamy Tuscan shrimp orzo rest for 1–2 minutes to thicken slightly. Adjust seasoning, add a squeeze of lemon juice if desired, and serve immediately.
