Season the shrimp: Pat shrimp dry with paper towels and season with salt and pepper.
Sear the shrimp: In a large skillet, melt 2 tablespoons butter over medium-high heat. Add shrimp in a single layer and cook 1-2 minutes per side until pink and just cooked through. Remove to a plate and set aside.
Sauté the garlic: Reduce heat to medium. Add the remaining 1 tablespoon butter and the minced garlic. Cook for 30 seconds until fragrant — don't let it brown.
Deglaze: Pour in the white wine and scrape up any browned bits from the bottom of the pan. Let it simmer for 1 minute.
Build the sauce: Add the chicken broth and cream cheese. Stir continuously until the cream cheese melts and the sauce is smooth.
Add the good stuff: Stir in sun-dried tomatoes, Italian seasoning, and red pepper flakes if using. Let simmer for 2-3 minutes until slightly thickened.
Wilt the spinach: Add the spinach and stir until just wilted, about 1 minute.
Finish: Stir in the parmesan cheese. Return the shrimp to the pan and toss to coat in the sauce. Taste and adjust seasoning.
Serve: Spoon over cooked pasta if desired, or serve with crusty bread. Garnish with fresh basil or parsley.