Basically you need to lose a candy heavy level, that has an easy to avoid final turn or two mechanic, till you have max turns and just try and farm it and get a small mountain that way. Then repeat until you have spent 250+ gold and make the whole thing pointless.
Ah, I remember what a great event event this was when they did the first test run. I actually won it once back then! No chance now. This event has been totally ruined and belongs on the scrap heap.