Put in a large bowl and add the buttermilk. Roughly chop the leaves from half the parsley, if using, and return the rest to the fridge. Stir the chopped parsley, rosemary, sugar, salt and pepper ...
if you don't have a ready supply of buttermilk, you can make a quick substitution for buttermilk by souring some fresh milk. Add 1 tbsp of lemon juice to every 100ml of milk called for in the recipe.