If your pistachios are whole, shell them first then place into a food processor and blitz until they resemble bread crumbs. Use frozen blueberries if needed. Build the cake at least 1 hour before serving. It keeps in the fridge for a couple of days, getting more chewy and delicious.
- Preheat the oven the 150C. Line two baking trays with paper. Draw 2 x 23cm circles.
- For the meringues, beat the egg whites until light and fluffy. Slowly add the caster sugar, beating until the meringue is thick and glossy. Fold through the icing sugar. Save 2 or 3 tablespoons of pistachio and coconut for garnish. Add the remaining to the meringue, stirring gently. Spoon the mixture evenly on two baking sheets, spreading with the back of a spoon. Bake for 1 hour, swapping around in the oven halfway through for even cooking. Turn the oven off and allow it to cool.
- For the filling, beat the mascarpone with the egg yolk and ¼ cup sugar until thick. Beat the egg white until stiff with the remaining sugar. Gently fold through the mascarpone.
- When ready to assemble, peel the paper from the meringues and place one on a plate. Top with the mascarpone, sliced peaches and most of the blueberries, reserving a few for garnish.
- Place the second meringue on top and garnish with slices of peach and blueberries. Sprinkle over the leftover coconut and pistachios. Leave it in the fridge until ready to serve.