Pat the shrimp dry and season. Use paper towels to remove excess moisture so you get a good sear.
Sprinkle with salt, pepper, and a pinch of Italian seasoning.
Sear the shrimp. Heat olive oil and 1 tablespoon butter in a large skillet over medium-high. Add shrimp in a single layer and cook 1–2 minutes per side until just pink and curled. Transfer to a plate.
Do not overcook—shrimp finish in the sauce later.
Sauté aromatics. Reduce heat to medium. Add remaining butter. Stir in garlic and cook 30 seconds until fragrant.
Add sun-dried tomatoes and cherry tomatoes and cook 1–2 minutes to soften.
Build the sauce. Pour in broth and scrape up any browned bits. Simmer 1–2 minutes. Stir in heavy cream, Italian seasoning, and red pepper flakes.
Bring to a gentle simmer (not a hard boil).
Add Parmesan and thicken. Lower heat and whisk in Parmesan until melted and smooth. Let the sauce gently bubble for 2–3 minutes to thicken slightly. If it gets too thick, splash in a little extra broth.
Wilt the spinach. Stir in spinach and cook 30–60 seconds until just wilted.
Finish with shrimp and lemon. Return shrimp and any juices to the pan.
Stir to coat and warm through for 1 minute. Add lemon zest and juice. Taste and adjust salt, pepper, and heat.
Serve. Garnish with chopped basil.
Pair with zucchini noodles, spaghetti squash, roasted broccoli, or cauliflower mash for a complete low carb meal.