What to do with all the egg whites?

After baking kueh bangkit, pineapple tarts and osmanthus melts, I was left with a lot of egg whites as the recipes above used only the egg yolks. 

Macarons - The Italian Way

Front clockwise: Matcha sprinkled shell with bitter sweet chocolate filling, Chocolate shell with bitter sweet chocolate filling, Vanilla shell with passion fruit curd, Cocoa powder sprinkled shell with
bitter sweet chocolate filling, Raspberry sprinkled shell with white chocolate raspberry filling.

It was quite a fearful first attempt for me a few years ago to make macarons. I wanted to make them and was reading as many blogs as I can on the subject matter. (such as this blog)  I was so impressed at the passion of these bloggers as they went to the extend of very systematically showing the hows and whys in making and breaking one's macarons. I am thankful for all their effort and finally pluck up my courage to make them.