Steam the cauliﬂower ﬂorets for 8–10 minutes, or until just tender. Meanwhile, melt the butter in a frying pan. Add the breadcrumbs and fry on medium heat, stirring constantly, until golden – take care not to let them burn. Remove the pan from the heat, season to taste with the salt and white pepper and keep hot.
Remove the yolk from the egg and pass it through a small sieve. Finely chop the white. Arrange the cauliﬂower ﬂorets in a heated, shallow dish and quickly spoon lines of buttered crumbs, egg white, yolk and parsley on top. Alternatively, pour the crumbs all over the cauliﬂower, then sprinkle on the egg white, yolk and parsley.
Broccoli Polonaise: Simply substitute broccoli florets for the cauliflower and proceed as directed above for cauliflower.