Pre-heat the oven to 120°C/gas mark ½. Grease and line 2 baking sheets. Whisk 2 egg whites until fairly stiff. Measure out 100g of caster sugar and add one tablespoon at a time to the egg whites, whisking continuously until the mixture is stiff and glossy. Dollop 8 equal spoonfuls of the mixture onto the baking sheets, leaving plenty of room between each one. Make a hollow in the centre of each then bake for 1¾-2 hours. Remove from the oven and leave to cool. Take 300g of strawberries and 300g of raspberries and set a few aside. Roughly chop the remaining strawberries and gently mix with the raspberries and 3 x 120g pots Activia Intensely Creamy Sumptuously Strawberry Yogurt. Spoon into the meringues. Chop 80g of unsalted pistachio nuts and decorate each meringue with the remaining berries, a sprig of mint, the chopped pistachios and a dusting of icing sugar.