When placing candle on cake, right-click the cake and the candle dupes.

If you place a candle on a cake, then right-click on it multiple times, candles will appear, as if it fails to remove the candle from the cake. You can do this infinite times and you have to break the cake to remove the candle along with it. Sorry, but I don't have video of this happening, but I will probably add it later on.