Treat me: Kumara and cardamom cake

On Monday night I went to the official opening of Le Cordon Bleu in Wellington, which was a veritable who's who of the New Zealand food scene. Even the Prime Minister was there, presumably because he pulls on a barbecue apron whenever a member of the royal family is in town.
I'm not sure what - or who - caused the fire alarm that saw us all stand outside in the pouring rain for 20 minutes and I had to leave before the hotly-anticipated canapes came out, but it was great to see so much interest in the local food scene. Perhaps the nicest words came from Mr Cordon Bleu himself, Andre Cointreau, who praised New Zealand produce (even the wine).
I'm not suggesting for a minute that it's up to Cordon Bleu standards, but this cake makes the most of one of our most underrated indigenous ingredients, the humble kumara.

Kumara and cardamom cake
It's been a bit grim for kumara growers 'up north' this year, but there are still plenty around. I love kumara every which way (including this way), but this was my first time trying it in a cake. It's worked so well that I've decided to make this my entry for this month's Sweet New Zealand, hosted by the lovely Sue of Couscous and Consciousness. The easiest way to cook kumara is to bake it in the oven - then you can just scoop out the flesh. Whatever way you cook it, let the mash cool to room temperature before adding it to the mixture.

200g unsalted butter, softened
200g caster sugar
1 tsp vanilla extract
4 eggs, at room temperature
150g ground almonds
2 tsp ground cardamom
2 tsp baking powder
1/4 tsp salt
200g mashed kumara (or sweet potato)

Heat the oven to 175C and grease and line a 23cm ring tin.
Cream the butter and sugar together until light and fluffy, then beat in the vanilla. Add the eggs, one at a time, while continue to beat. Add a spoonful of the ground almonds along with each egg - this will help prevent curdling. When all the eggs have been added, stir through the cardamom, baking powder and mashed kumara until combined.
Pour into the prepared tin and bake for 45-50 minutes, until a skewer comes out cleanly. Leave in the tin for 10 minutes, then turn out to a rack to cool.

When the cake is cold, you can drizzle over an icing made from a cup of icing sugar sifted into a small bowl with 1/2 - 1tsp ground cardamom, 1tsp butter and a tablespoon (or so) of boiling water. Add more water, cautiously, to get to the right consistency.

Have a great weekend everyone. I'm planning to spend it studying Jerusalem and thinking deeply about our garden. Oh, and having houseguests, one of whom is 11 months old. Perhaps I should revise those first two aims. Hope you have a good one x