Start by marinating the chicken. Cut the chicken into mouth size pieces and place in a bowl. Add in the yoghurt, garlic, spices, the lemon juice and mix. Ideally you would leave this overnight but if you can't then 30 minutes as a minimum. Whilst this is marinading start making the sauce, this gives it time to cook down and thicken.
Add the ginger and garlic to a pan with coconut oil. Add in the chopped chilli and finely chop the coriander stalks then add this in too. Add in the spices to coat the mix and the tomato puree. Once this is all combined, stir through the butter until completely melted and the pan is totally glossy. Give this a good stir then add in the cream. Turn the heat right down. In a separate medium pan, on a medium heat, melt down a knob of butter or coconut oil. Once completely melted, add in the chicken. Cook the chicken for about 8 minutes then add the the pan with the sauce to finish the cooking. Cook until the chicken is completely cooked through and the sauce has thickened.
Preheat the oven to 200C. Roll out the puff pastry so its a 1 1/2 centimeters thick. Using a 10 centimeters diameter bowl, if it's a bit bigger that's ok, cut out four circles. Any spare pastry can be cling wrapped and kept in the fridge for another day. On half of the circle divide the chicken, leaving 1 centimeter gap around the edge. Fold over the pastry and pinch edges together in whatever pattern you like. You can use a fork to seal completely. Place on a baking tray. Add the pinches of spices to the egg and using a pastry brush, brush the egg wash over the top of the pasties, use the egg wash to ensure the pastry is sealed round the edge, then prick the top. Place in the oven for around 18 minutes, until the pastry is golden and crisp. Place the extra sauce into a dipping bowl on the side and garnish with coriander leaves if you wish.