After trying both the white truffles and black truffles, I can understand why white truffles cost more. The smell and flavour is more intense for white truffles, compared to black. A small amount of white is enough to provide the taste and flavouring. Black truffles cost about a third of white truffles. Personally, I prefer white truffles!
Here's recollecting what we had.
(Note from dailydelicious: you can bake the meringue and keep it in the airtight container for 2-3 days at room temperature. For me, I baked the day before.)