Stir the flour, polenta, baking powder and salt together in a bowl. Crack in the egg.
Add the buttermilk to the batter and stir well.
Slice the top and tail from the spring onions. Drain the sweetcorn and add to a small food processor with the jalapeños, spring onions and half of the coriander, stalks and leaves.
Blitz to a paste and mix into the bowl of dry ingredients along with the buttermilk and egg.
Transfer the mixture to a tall glass.
Skewer a hot dog onto each stick and roll them around on a plate of cornflour.
Heat the oil in a deep fat fryer to a temperature of 180°C. Dunk the hotdog into the glass of batter and then lower straight down into the hot oil to fry for 4-5 minutes, until golden brown. You’ll need to cook just a few at a time.
Chop the rest of the fresh coriander and mix into the mayonnaise with the zest from the lime.
Once golden brown, drain the corndogs on kitchen paper.
Serve with plenty of the lime and coriander dip. Makes 6