According to the wedding cake book I am using as a reference, I will need about 40 cups of buttercream. This is to fill and frost a 4-tier cake (14 inch, 10 inch, 8 inch and 6 inch) with each tier being a 4-layer cake. This insane amount of buttercream equates to making about 6 batches of buttercream because each batch churns out 7 cups limited by the size of the mixing bowl.
One of the nightmarish things that can happen on the day of the cake assembly is running out of buttercream so I decided to build up some buffer and make 7 batches instead. That's a whopping 49 cups!
And this means 56 egg whites and 56 wasted egg yolks. I wish there was something useful I can do with the yolks. Maybe make a bucket of homemade mayo? I will not disclose the exact amount here but let me just say 7 batches of buttercream equals many sticks of butter.
The steps to making the italian meringue buttercream is quite simple but it takes awhile because of the cooling time required. Basically, a hot molten sugar syrup is slowly mixed into a batch of whipped up egg white meringue and before you can add any butter, the meringue sugar mixture needs to be cooled completely in a mixer on high speed. This process can take up to 25 minutes. So making 7 batches of buttercream was definitely not quick.
Voila. Seven batches of silky vanilla buttercream done!