Rinse the mackerel and pat it dry
Remove the head, guts, and scales if needed
Make a few diagonal cuts on each side
Season with salt, pepper, and lemon juice
Heat a pan, grill, or oven to medium-high
Add a little oil to the cooking surface
Cook the mackerel skin-side down first
Cook for 3 to 5 minutes per side, depending on size
Flip carefully and cook until the flesh flakes easily
Check that the center is opaque and fully cooked
Serve hot with lemon or herbs