If you have no buttermilk, 170ml regular milk combine with 2 teaspoons lemon juice and it let sit for 10 minutes before using.
Made this for my mum's bday, it didn't come out as I expected. 1) the cake didn't rise, so was more brownie like. 2) the icing never got to spreadable consistency despite LOTS of whipping, so couldn't sandwich the layers together. BUT it tasted lovely - I served it as a single layer slice with a spoonful of the chocolate 'icing' drizzled over, a spoon of whipped cream and some raspberries, and everyone loved it. - 24 May 2017