Truffle problem

So I got good pizza great pizza roughly a year ago and have been playing ever since, I finished all the chapters and im still playing just for fun. I have found from other reddit posts/tiktoks that people have avacodo and truffle. I just wanted to know if it was part of an event or something because i dont see them in the shop or to grow anything in my garden, and at this im just getting bored of the ingredients and I also love how avacado looks. Just wondering!