Season your tuna steak with a sprinkle of salt and black pepper.
Add your lemon zest to the tuna and pack your tuna steaks in dukkah seasoning, pressing onto the tuna so it doesn't fall off, once cooked it will adhere to the fish.
Grill you tuna steaks briefly, about 10-15 minutes turning at about 5-7 minutes. You don't want to overcook your tuna steaks, in fact keeping them rare in the middle is ideal.
To make your lemon sauce, add lemon juice, zest, black pepper and salted butter together then drizzle over the freshly cooked tuna.
Serve with couscous, cauliflower rice, rice or roasted or sautéed vegetables.