Chocolate and pistachio pavlova

Method

1. Preheat the oven to 121ºC. Line a rimmed baking sheet with baking paper. Using a pencil, in the center of the parchment paper, lightly trace a 23cm circle along the bottom of a cake pan.
2. Place the chopped chocolate in a small heat proof bowl. Place in the microwave and heat in 30 second intervals, stopping to stir the chocolate with a spatula until it has melted, about 1-1.5 minutes. Set aside to cool.
3. In a medium heat proof mixing bowl, add the sugar and egg whites. Place the bowl over a large saucepan filled with 2.5cm of simmering water set over a stove. Make sure the water does not touch the bottom of the bowl. Using a hand whisk, gently whisk the mixture until all the sugar has dissolved and the mixture registers to 75ºC (approx 5-8 minutes).
4. Remove the bowl from the saucepan and set over a towel shaped in a ring (this will prevent it from moving on the counter). Fit the KitchenAid stand mixer with the whisk attachment. Place the whisk into the warmed egg white mixture, and turn the mixer to speed 9. Mix until it forms stiff peaks and has a sheen (approx 5-8 minutes).
5. Reduce to speed 3, and while mixing, add the vinegar, cornstarch, and vanilla. Turn the mixer back to speed 9 and whip for another 30 seconds. Turn off the mixer.
6. Gently fold in the pistachios. Drizzle the melted chocolate (make sure it's not too hot or it will deflate the meringue) over the top of the meringue.
7. Dollop a bit of meringue onto each corner of the rimmed baking sheet. Press the parchment (marked side facing down) onto the baking sheet to help secure the paper.
8. Using a spatula or large spoon, gently mound the meringue in the center of the drawn circle. Spread and smooth the meringue, building a 23cm round that is slightly higher along the edges. The finished round should measure about 4cm high.
9. Place the meringue in the center rack in the oven. Bake until the meringue is light in color, dry, and releases easily from the parchment when lifted with a large offset spatula (approx 1-1.5 hours).
10. Turn off the oven, and prop the door open. Let the meringue cool (undisturbed) for another 1.5 hours, then remove the meringue from the oven and let cool completely on the baking pan.
11. While the meringue is cooling, make the topping. In a small bowl add the raspberries, sugar, and lemon juice. Toss to combine, and set aside for 15 minutes.
12. To make the raspberry whipped cream, add the heavy whipping cream, confectioners sugar and vanilla extract to a large mixing bowl.
13. Mix on speed 4 until the whisk starts to leave a trail (about 1 minute), then increase to speed 8 and whip until the whipped cream forms medium peaks (another 30-45 seconds). Reduce to speed 3 and gradually add the raspberries. Mix until the raspberries have broken up, then increase to speed 8 and whip for an additional 30 seconds. Place the bowl in the fridge until ready for assembly.
14. To assemble your pavlova, use a large offset spatula (or maybe two, one on each side), and carefully remove the meringue from the parchment. Slide the meringue on a serving platter. Mound the raspberry whipped cream onto the meringue, creating an even layer. Then, using a slotted spoon, evenly spoon the raspberry mixture over the whipped cream. Garnish with the chopped pistachios. Let the meringue sit for 10 minutes before slicing and serving.