Fill an 8-inch cast-iron skillet half-way up with oil. Heat the oil to 360-375ºF.
In a large bowl, mix together the besan, red chili flakes, salt, baking powder, sliced chilli pepper, cilantro, and sliced onion.
Slowly add in the water, while mixing with a wooden spoon or your hands. Vigorously mix for a couple of seconds. The batter should be thick, almost like heavy (double) cream and there should be air bubbles throughout.
Once the oil is heated, carefully place in heaping tablespoonfuls of batter into the hot oil. Try not to overcrowd the oil because it will result in greasy pakoras. Fry until the pakoras are a pecan-brown. Drain on a cooling rack placed over a cookie sheet.
Repeat with the remainder of the batter.
Serve right away, and enjoy.