Preheat oven to 200C/180C Fan/Gas 6. Place a sheet of kitchen foil on the middle shelf.
Rub the sweet potato all over with half a tsp of of olive oil. Pierce the skin several times with a sharp knife and place directly onto the top shelf of the oven and bake for 1 hour.
Mix the sauce ingredients together in a small bowl, adding a splash of water if it’s a little thick. Season and set aside (the further in advance you do this, the better, for the flavours to develop).
Meanwhile, make the dough: tip the flour into a large bowl, stir in the salt and make a well in the middle. Gradually pour in 160-180ml water, mixing together to form a rough dough.
Turn out onto a lightly floured surface and knead for 5 mins, until you have a smooth, elastic ball of dough. Cover with an upturned bowl or a clean tea towel and leave to rest for 20 mins.
Heat a splash of olive oil in a large frying pan and fry the leek and garlic gently for 5 mins until soft. Tip into a large bowl. Scoop the cooked sweet potato from its skin and put in the bowl with the spinach and a pinch of chilli flakes. Season to taste.
Divide the dough into four equal pieces. Roll each into a thin round, roughly 20cm in diameter. Spoon a quarter of the sweet potato mixture onto one side of a piece dough, brush the edge with water and fold the opposite edge over to enclose the filling – it should be a semicircle.
Press the edges together to seal, making sure there’s no air trapped inside. Repeat with the remaining
dough and filling.
Heat a little oil in a large frying pan over a medium heat and fry the bolani for 2 mins on each side, until crisp and golden. Drain on kitchen paper and serve with the sauce for dipping.
