For the dough, combine the flour, oil, baking powder and salt in a large bowl. Mix in the warm water bit by bit, until it comes together to form a medium soft dough. Knead vigorously for at least five minutes, using your knuckles. Cover the dough with a damp cloth and set aside.
For the filling, drain the soaked lentils and lightly mash them with a fork. Heat the sunflower oil in a pan and add the cumin seeds and asafoetida. When the seeds are crackling, add the lentils and peas and sauté for about two minutes.
In a pestle and mortar, grind the ginger and green chillies to make a paste. Add the paste to the pan with the chilli powder, garam masala, amchur powder and salt and stir for a couple of minutes. Add the hot water to the pan, put the lid on and simmer for around 12 minutes, or until the lentils are cooked.
Lightly flour a work surface and roll the dough into golf-ball sized dough balls. Press each ball into a circle about 10cm/4in in diameter and 5mm/¼in thick. If the dough becomes dry, lightly oil your hands as you roll each ball.
Place one tablespoon of the filling mixture in the centre of each circle. Pull the dough edges up, pinching together and twisting into a moneybag shape.
Place the parcels on a lightly floured work surface and gently flatten, pressing the edges to seal in the filling.
Heat the sunflower oil in a large wok or deep-fat fryer until a small cube of bread sizzles and turns golden when dropped into it. (CAUTION: hot oil can be dangerous. Do not leave unattended.)
Deep fry the kachoris for approximately five minutes, or until golden-brown on both sides and puffed up.