While coconut and almond macaroons are well known around here, hazelnut macaroons are quite a rare thing at least outside Germany. And that really is a pity, as they are darn delicious, if I may say so. And easy to make.
As long as I can remember, well almost that long, you can buy ground hazelnuts in Germany. They can be found in the baking aisle in most supermarkets. Just until fairly recently, it was pretty hard to get them in Belgium and the Netherlands. But also there, they are finding their way into the supermarkets. And you can now order ground hazelnuts or hazelnut meal at most of the online nut and seed shops.