Peel the outer onion layer and cut the heads into round slices. Carefully divide them up into separate layers.
Put the resulting onion rings in a large colander or strainer and pour cold water over them. Leave them to drain a bit and prepare the breading.
Beat the egg with the milk. Add salt, black pepper and curry to taste and flour to get a sludge.
Roll the onion rings in flour first and then in the prepared breading mixture.
Fry in oil until golden. Take them out onto a cooking grid to drain away the oil.