01 - Preheat oven to 400°F. Lightly grease a medium baking dish with olive oil.
02 - Heat 2 tbsp olive oil in a large skillet over medium heat. Cook onions until translucent, about 3 minutes. Add garlic and cook for 1 minute more.
03 - Stir in sun-dried tomatoes and spinach. Sauté until spinach is wilted, approximately 2 minutes.
04 - Pour in heavy cream and bring to a gentle simmer. Add Parmesan cheese, Italian herbs, red pepper flakes, salt, and black pepper. Simmer for 2-3 minutes until sauce thickens slightly.
05 - Add shrimp to the skillet, stirring to coat evenly with the sauce. Remove from heat.
06 - Transfer mixture to the prepared baking dish. Top evenly with shredded mozzarella cheese.
07 - Bake uncovered for 15-18 minutes until shrimp are pink and cheese is melted and golden.
08 - Serve hot, garnished with additional Parmesan or chopped parsley if desired.