Which challenge to put it in ? The candlelight or the egg challenge ?
How I did it :
I removed the yolk from a boiled egg, put in part of a candle instead and stuffed the yolk back in.
Then dropped wax from another candle on the yolk to prevent it from burning black immediately.
Set the egg on a mirror with yellow-tag, with yellow cardboard behind it
(I learned/copied the technique from MFC from previous challenges,
it works really well and does not leave hard shadows,
which you do get when putting the cardboard underneath).
I took test shots to determine exposure, before lighting the candle.
One 150W halogen light from the right.