Siniyet samak bi tahini (baked sea bass with tahini)

Steps

1. Heat the oven to 200°C. Pat the fish fully dry and cut 2–3 deep diagonal slashes to the bone on each side. Season inside and out with the salt and pepper. Slice one lemon and tuck a few slices and 2 smashed garlic cloves into the cavity.
2. Toss the potatoes and onion with 2 tbsp olive oil, a pinch of salt and 1 tsp sumac. Spread in a baking tray and roast alone for 20 min.
3. Mix 2 tbsp olive oil, the juice of half a lemon, 2 crushed garlic cloves, the za'atar and the other 1 tsp sumac into a paste. Rub it all over the fish and into the slashes.
4. Lay the fish on the potatoes, drizzle the last 1 tbsp olive oil over everything, and bake 20 min, until almost done. Don't flip the fish.
5. While it bakes, whisk the tahini with the juice of 1 lemon, 1 crushed garlic clove, a pinch of salt and the cumin if using. Add the water a splash at a time until smooth and pourable like cream.
6. Pour the tahini over and around the fish and potatoes. Bake 10 min more, until set and lightly golden.
7. Warm 1 tbsp oil, turn off the heat and stir in the dried mint for a few seconds. Drizzle it over the fish, scatter the nuts and a pinch of sumac, rest 2 min, and serve. Lift off the top fillet, then peel the spine away.