Peel a medium-sized cucumber and cut into very thick slices. Scoop out the centre of each piece with a melon baller making sure not to cut all the way through. Set aside.

Mix together 125ml Greek yogurt with 1 small garlic clove, crushed, some finely chopped mint (a dozen leaves), a good squeeze of lemon juice and a drizzle of olive oil. Season with sea salt. Adjust the seasoning to taste and set aside.

On a large plate sprinkle on ¼ cup za’atar and 2 tbs sumac. Cut a 500g loin of tuna into large chunks and dredge on all sides with the spice mixture.

Heat a large pan with a drizzle of rapeseed/canola oil. Quickly sear the tuna on all sides, and immediately remove to a platter (the meat should still be quite raw inside).

Divide the tuna between four plates, add a few slices of cucumber (hollow side up), fill with the yogurt mixture and sprinkle with nigella seeds. Drizzle a little olive oil all around before serving.

Serves 4 as a starter.