Preheat oven to 350°F (175°C).
Sauté onion in oil until soft, then add garlic and spinach—cook until wilted.
Let cool, then mix in cream cheese and sun-dried tomatoes.
Season salmon with Creole seasoning and spread on the filling.
If needed, freeze for 10 minutes to firm it up before rolling.
Roll tightly, secure with skewers or twine, slice into pinwheels, and lay on lemon slices in a cast-iron pan.
Top with butter and more seasoning.
Bake for 15 minutes, then broil for 3–5 minutes until golden.
Garnish with parsley.