Authentic amaretti are crispy airy and bittersweet.....w/ mysterious ingredients like apricot kernels....and very pricey. Hard to duplicate.
Here's my solution:
Mound whole almonds, hazelnuts on sheetpan. Pour over vanilla sugar syrup flavored w/ droplet of almond extract. Then roast til caramelized.
Grind to a coarse crunch---sprinkle over layers.
Liz, you are probably the best and most ingenious cook here :-)
-JT