Preheat oven to 425°F (220°C).
Flatten thicker parts of chicken for even cooking and place in 9×13-inch baking dish.
Mix ¼ tsp salt, Italian seasoning, smoked paprika, and ¼ tsp black pepper.
Drizzle chicken with olive oil and rub seasoning on top.
Whisk heavy cream, garlic, remaining ¼ tsp salt, ⅛ tsp pepper, and red pepper flakes (optional).
Stir in sun-dried tomatoes and Parmesan to the cream mixture.
Pour sauce around chicken.
Bake 16–20 minutes until internal temperature reaches 165°F (74°C).
Remove from oven and stir in fresh spinach to wilt in the hot sauce.
Garnish with basil or parsley if desired and serve immediately.
