1. Clean mackerel by removing the innards. Keep head and tail and skin intact.
2. Soak it in water and lemon mixture for about an hour.
3. Preheat grill to medium high.
4. Season fish with pepper, and chili flakes.
5. Stuff fish cavity equally with lemon slices, cedar leaves, parsley, and capers. Dot with butter. Sprinkle dill seeds.
6. With cooking twine, tie fish on the top, middle, and bottom to hold stuffing while grilling.
7. Brush fish lightly with oil.
8. Roll a kitchen towel, pour some cooking oil on it. With tongs hold the towel, and grease the grilling rack lightly with oil.
9. Place fish on grill and cook for about 3-5 minutes per side or until golden brown with nice grill marks.
10. Cut off and remove string.
11. Serve whole mackerel with lemon wedge garnish.
Baste fish with lemon, or any kind of flavoring you like, if desired.