These turned out pretty good - firm on the outside and chewy on the inside.

Preheat the oven to 200 C.

In a bowl mix together:
200g ground almonds
1 cup of caster sugar
1 teaspoon ground cardamon
2 egg whites

You can use a mixer but just a fork or spoon does fine. My paste was a bit gloopy so I added some rice flour. Drop teaspoon fulls onto a greased baking sheet. Leave room for spreading. Press a blanched or sliver of almond on the top of each macaroon, bake for 10 minutes.
Thanks to Sarah M for Nigella's recipe.