Place flour in a deep, heavy based pan. Add ginger-chilli paste, chilli powder, salt, heeng and haldi, and mix. Now add the yogurt, a little at a time, so as to form a smooth paste, without any lumps, and then the water.
Place the pan over high heat, and bring to a boil, stirring all the time. Keep cooking and stirring till you reach a paste like consistency, increasing or decreasing the heat according to your ability to avoid scorching.
It is cooked enough, when you separate a portion of it from the rest with a stirrer and you can see the bottom of the pan, which gets covered gradually (if it gets covered immediately, it is too thin). Another test is to spread a tsp of the batter on to an ungreased surface, when cool, it should come off clean.
With the help of a rubber spatula spread the mixture onto an ungreased surface, in as thin a layer as possible and leave to cool.
Heat the oil in a small pan and add the sarson, kadhi patta and sabut lal mirch. Stir a few times and then spread over the layer. Sprinkle all but 1 tbsp of the coriander and 1tbsp of the coconut over it, and pick up the lal mirch and keep aside.Cut this layer into strips roll up each strip like a scroll, as firmly as you can, without breaking them.
Arrange them on to a serving dish. Garnish with the rest of the coriander, coconut and peppers. Serve.