This is a total cheat because I didn't actually make it. My mom is visiting right now, and she loves cake. She saw this one in the Nigella Lawson book "How to be a Domestic Goddess" and had to try it. It was made in my kitchen, and I was there watching, but I can't actually take the credit.
250g softened butter
250g softened marzipan
150g caster sugar
1/4 tsp almond essence
1/4 tsp vanilla extract
6 large eggs
150g self raising flour
25cm springform tube pan, or patterned ring mould, buttered and floured.
Preheat to 170c/325f
Chop the butter and marzipan to make them easier to break down, and put them in a food processor with the sugar. Process till combined and pretty well smooth. Add the almond essence and the vanilla extract and process again. Add the eggs one at a time through the funnel, processing again each time. Tip the flour down the funnel, processing again, and then pour into the prepared tin.
Bake for 50 min, but check from 40. When the cake looks golden and a cake tester comes out clean-ish, remove from the oven and cool before turning out.
I know it sounds like this would be overly sweet, with the marzipan and all, but it's really not. It's truely a beautiful thing. It has the consistancy of a pound cake, but really really almond-y. It really was super easy too, and not just because it wasn't me making it. It also kept well and was just as good if not better the next day.