Meghan and Harry Walking On Eggshells Over Wedding Cake

5/18/2018 6:41 AM PDT

Meghan and Harry's Wedding Cake Filled with 500 Eggs

The cholesterol level among the Royals is about to rise, because Meghan Markle and Prince Harry's wedding cake is filled with eggs -- 500 of them!

California baker Claire Ptak is hard at work finishing up the staple for any wedding ... this cake contains 200 Amalfi lemons, and 10 bottles of elderflower cordial.

The 3 layers are each different sizes ... unusual, says the baker. She calls her creation an 'ethereal layered lemon and elderflower cake.' It's actually a sponge cake of sorts ... the sponge is sandwiched with lemon curd and swiss meringue buttercream.

The cake will be served at Windsor Castle, where roughly 600 guests will chow down.

24 Hour Fitness anyone?