Heat the oven to 160C/140C fan/gas 3. Mix the tomatoes, garlic, half the oil, tamarind and sugar together, along with a generous pinch of seasoning. Tip onto a baking tray and put in the oven for 25-30 mins or until sticky and roasted. Leave to cool a little.
Heat the remaining oil in a large frying pan over a medium heat, then add the leek and spring onions, stirring occasionally until softened, about 10 mins. Leave to cool completely, then tip into a bowl and mix with the spinach, feta, roasted tomatoes, eggs, coriander, smoked paprika and seasoning.
Heat the oven to 200C/180C/gas 6. Brush a sheet of filo with melted butter, then lay another sheet on top and brush with butter again, keeping the rest of the filo covered with a clean, damp tea towel to stop it drying out, Spoon a third of the filling along the long side of the rectangle and gently roll into a long tube. Repeat this two more times until you have used all the filo and filling. In a round pie dish, or round ovenproof pan, carefully coil the three filo rolls from the outside of the dish in towards the middle, so you end up with a large spiral. Don’t worry if it cracks a bit – you can layer the filo to cover any cracks. Brush the whole spiral with more butter, sprinkle over the chilli flakes and bake for 50-60 mins until deep, golden brown. Scatter over the extra coriander to serve.