Step 1

Heat the oven to 180C/ fan 160C/gas 4 and butter and line a 20cm x 10cm x 7cm 900g loaf tin with a long strip of baking paper.

Step 2

Put the pistachios and sugar in a food processor and whizz until fine. Add the butter, soured cream, eggs, flour, baking powder, bicarb, vanilla extract and lime zest, and whizz until smooth. Scrape into the prepared tin and bake for 50-55 minutes or until a skewer poked into the centre comes out clean (if it browns too quickly, cover with a sheet of foil). Cool for 20 minutes in the tin, then turn out onto a wire rack to cool completely.

Step 3

To make the icing, mix enough lime juice into the icing sugar to make a drizzle-able icing. Spoon over the cake then finish with the pistachio slivers.