Heat oven to 160C/140C fan/gas 3. Grease a deep 20cm round cake tin with a little bit of the butter, then line with greaseproof paper or baking parchment. Wrap a couple of sheets of newspaper around the outside of the tin, then secure with string.
In a food processor, whizz the almonds with the flour until the mix resembles crumbs. Beat the butter and icing sugar until light and fluffy. Beat in the eggs, one by one, then fold in the flour and almonds, dried fruit and brandy. Scrape into the tin, level the surface and bake for 1 hr 15 mins, until a skewer poked in comes out clean. Cool in the tin.
When the cake is completely cold, make the icing quickly by beating the butter, jam and icing sugar until pale. Don’t allow the butter to get too warm or overbeat as the icing might split. Swirl all over the cake, then leave in a cool place to set (but not the fridge).