Prep the shrimp. Pat the shrimp dry with paper towels.
Season both sides with salt and pepper. Dry shrimp sear better and stay juicy.
Cook the cauliflower rice. Heat 1 tablespoon oil or butter in a large skillet over medium heat. Add the cauliflower rice, a pinch of salt, and cook 5–7 minutes, stirring occasionally, until tender and lightly steamy.
Transfer to a bowl, cover to keep warm.
Sear the shrimp. In the same skillet, add 1 tablespoon olive oil and 1 tablespoon butter over medium-high heat. Add shrimp in a single layer and cook 1–2 minutes per side until just opaque and lightly golden. Remove to a plate.
Do not overcook.
Sauté aromatics. Lower heat to medium. Add remaining olive oil and butter. Stir in garlic, sun-dried tomatoes, Italian seasoning, and red pepper flakes.
Cook 1 minute until fragrant but not browned.
Build the sauce. Pour in chicken broth, scraping up any browned bits. Simmer 2 minutes to reduce slightly. Stir in heavy cream and bring to a gentle simmer.
Melt in the cheese. Add Parmesan gradually, stirring until smooth.
If it seems too thick, splash in more broth. If too thin, let it bubble for another minute.
Add greens. Stir in spinach and cook until just wilted, about 1 minute.
Finish with shrimp and lemon. Return shrimp and any juices to the pan. Toss to coat and warm through, about 1 minute.
Stir in lemon juice. Taste and adjust salt, pepper, and heat.
Serve. Spoon the creamy Tuscan shrimp over warm cauliflower rice. Garnish with parsley and extra Parmesan if you like.
Add lemon wedges on the side.