Tip the couscous into a large mixing bowl and stir in the raisins, 1 tsp each turmeric and cinnamon and a good pinch of salt. Pour in 300ml boiling water, stir together and cover with a large plate. Set aside to soak.
Pod the broad beans. Fill a large saucepan with boiling water and add a pinch of salt. Return to the boil and add the beans. Blanch for 2 mins, then use a slotted spoon to transfer them to a bowl. Keep the hot water in the saucepan for later.
Peel and finely slice the red onion and add to the broad beans. Zest in the lemon and squeeze in half of the juice. Sprinkle in a little salt and pepper and mix well. Pick the mint leaves, shred, then slide them into the bowl.
Peel and grate the garlic into a bowl. Squeeze in the remaining lemon juice, and add 1 tbsp tahini, 1 tbsp olive oil and 3-4 tbsp cold water. Add a little salt and pepper and mix together into a dressing.
Slice the cabbages lengthways into quarter wedges. Bring the large saucepan of water back to the boil and add the cabbage. Simmer for 3-4 mins, drain well and transfer to a plate.
Pour 1 tbsp oil into a large frying or griddle pan and bring to a high heat. When smoking hot, carefully add the cabbage wedges, cut-side down, and cook for 3 mins, till charred, then turn and cook on the other cut side, for 3 mins, till charred.
Fluff up the couscous with a fork and stir through the mint, broad beans and red onion, along with the lemony juices, another pinch of salt and pepper and 1 tbsp olive oil.
Heap the couscous onto a couple of plates and top with wedges of the charred cabbage. Crumble over half the pack of feta, and spoon over the tahini dressing to serve.