Awesomecakes makes use of the '-cakes' suffix as an all-purpose strengthener, akin to '-pants' and '-tastic'. Thus, something that is awesomecakes is awesome to an especially bodacious degree.
A situation or occurrence which brings forth feelings of 1) joy, 2) elation or 3) excitement in the one who experiences it. Used to describe those rare situations which are "beyond awesome," and therefore require the inclusion of something ELSE awesome (such as cake) to capture the fullness of just how great and amazing it is.
Note: Things that are "awesomecake" do NOT necessarily have ANYTHING to do with cake.