I guess the ammonia must be the magic ingredient. I could not find and substituted baking powder, baking soda, and salt, and the result was the blandest cookie ever.

These are similiar to my aunts recipe. You must use the ammonia or it won't turn out right. You can find it at alot of german stores. YUM

I had the opportunity to find out exactly what hartshorn does for a recipe, since I accidentally forgot to bring it with me to the beach, where I first tried this recipe. The results of that batch were okay--others liked them--but to me they were heavy and dull. When I returned home and could actually use the hartshorn I'd bought for this recipe: oh, wow!!! This recipe--plus the hartshorn--is a holy grail for me. The texture is substantial but has a light, clean, dry crunch that I now know is characteristic of hartshorn. Do go to the trouble of finding some for these cookies; it's definitely worth it!

What a wonderful cookie! Sweet, crunchy, and full of the taste of almonds and butter. This should really bring back the use of hartshorn.