place the onions in the buttermilk to marinate for 30 minutes or overnight in the fridge covered with cling film.
In a second bowl, combine the flour, cornflour, spices, salt and pepper.
Preheat a deep fat fryer to 200˚C.
Remove the onions from the buttermilk and drain excess liquid. Toss them in the mixture of spiced flour to coat them well.
In batches if needed, deep the coated onions in the fryer and cook for 2 minutes or until well coloured and crispy texture.
Remove and drain on kitchen paper to absorb excess oil and enjoy while warm.