Pat the shrimp dry and season. Blot shrimp with paper towels.
Season with 1/2 teaspoon salt and 1/4 teaspoon pepper. This helps them sear well and taste seasoned all the way through.
Sear the shrimp. Heat 1 tablespoon olive oil and 1 tablespoon butter in a large skillet over medium-high. Add shrimp in a single layer.
Cook 1–2 minutes per side until just pink and curled. Transfer to a plate. Don’t overcook—they’ll finish in the sauce.
Sauté aromatics. Lower heat to medium.
Add remaining oil and butter. Stir in garlic and sun-dried tomatoes. Cook 1–2 minutes until fragrant.
Add red pepper flakes if using.
Deglaze. Pour in white wine (or broth). Scrape up browned bits. Simmer 1–2 minutes to reduce slightly and cook off alcohol.
Build the sauce. Stir in heavy cream and 1/2 cup broth.
Add Italian seasoning. Bring to a gentle simmer. Cook 2–3 minutes, stirring, until it thickens slightly.
Add Parmesan. Lower heat and stir in Parmesan until melted and smooth.
Taste and season with salt and pepper. The sauce should be creamy, savory, and a touch tangy from the tomatoes.
Wilt the greens. Add spinach and stir until just wilted, 30–60 seconds. If the sauce gets too thick, splash in a little more broth.
Finish with shrimp. Return shrimp and any juices to the skillet.
Simmer on low 1 minute to warm through. Squeeze in lemon juice for brightness. Adjust seasoning.
Garnish and serve. Top with chopped basil or parsley and extra Parmesan.
Serve over pasta, spooned onto rice, or with warm bread for dunking.