I've just found out what Opera Cake is. If that's a shocker, then consider I've also only just now found out that people make it with Matcha green tea. Coffee, almonds, and chocolate ganache are perfect for each other, and that's the basis of the Opera Cake as I understand it--however, I have to say that infusing something with Matcha, no matter what it is, has the minor side effect of making that creation instantly awesome.
Cereal, for example. Or donuts. Or heck, ice cream. You can't really go wrong with Matcha powder.
Note: that Green Tea Donut image is courtesy of Stephen's Blog. It's a good one, go check it out, especially if you love the concept of Japan as much as yours truly. The cake, of course, is from Canelle et Vanille. Thank you!