Preheat the oven to 140°C (130°C Fan, Gas Mark 1). Line a baking sheet with non- stick greaseproof paper or baking parchment and draw a 23cm (9”) circle on it using a plate or cake tin to guide.
n a large, grease free bowl and using a hand held or free standing electric mixer, whip the egg whites and Cream of Tartar until they hold their shape. Gradually add the sugar, whisking well between each addition, until they are very stiff and glossy. Gently fold in the Vanilla Paste, vinegar and cornflour.
Place the meringue mixture into a piping bag and cut off the end of the piping bag to create a 2cm hole. Pipe the meringue around the edge of the circle you’ve drawn onto the baking parchment. Continue piping the meringue to fill the centre of the circle, this will create your base. Once you have your meringue base pipe dollops of meringue around the edge of the circle to create a meringue kiss nest. Sprinkle 25g of chopped pistachios over the meringue nest and place in the oven to bake for approximately 1½ - 1¾ hrs until the meringue is dried out. Remove from the oven and leave to cool completely.
Peel the parchment away from the base of the nest and place on a serving plate. Whip the double cream to form soft peaks, stir in the Greek yoghurt, Vanilla Paste and Icing sugar. Spoon the mixture into the centre of the meringue nest and decorate with raspberries and the remaining chopped pistachios.