Preheat the oven to 180°C/160°C Fan/gas mark 4 and line a baking tray with baking parchment. Beat the egg whites until smooth peaks form, then beat in the sugar a spoonful at a time until the meringue is stiff and shiny. Sprinkle the cornflour over the meringue, then grate in the zest of 1 orange and add 2 teaspoons of lemon juice. Gently fold until everything is thoroughly mixed in. Mound onto the lined baking tray in a fat circle approximately 23cm/10inches in diameter, smoothing the sides and the top with a knife or spatula.

Place in the oven, then immediately turn the temperature down to 150°C/130°C Fan/gas mark 2/, and cook for 1 hour. Remove from the oven and leave to cool. When you’re ready to eat, turn the pavlova onto a large flat plate or board with the underside uppermost. Whip the cream until thick and airy but still with a soft voluptuousness about it, and set it aside for a moment. With a spatula, spread the orange curd on top of the meringue base. Now top with the whipped cream, peaking it rather as if it were a meringue topping. Sprinkle with the zest of the remaining orange and followed by the pistachios, and serve.