Hello again Janice!

Amaretto is a liqueur. I'm sure the "Spirit Shops" in Australia carry it.

"Amaretto is a distinctive blend of vanilla, almond and a variety of other nuts gathered from around the world. Its unique nutty taste and color (caramel)makes Amaretto a special delight when served over ice cream, ice or straight as an after dinner drink. So says the label on the back of my Bols Amaretto Liqueur bottle".

If you can't find Amaretto I wonder if adding a teaspoon of almond extract, and one more teaspoon of vanilla might bring the flavor closer to what the recipe calls for? However, I wouldn't worry with or without the Biscottis will taste good.