Chocolate Pavlova

Instructions

1. Preheat the oven to 275° (135° C) and place a rack on the bottom third of the oven. Trace a 6" (15cm) circle on a piece of parchment paper and set it, upside down, on a baking sheet.
2. Fit the whisk attachment to a stand mixer, then add the egg whites, salt, and cream of tarter to the bowl. Whisk on medium-high until medium soft peaks form, about 3 minutes.
3. Turn the mixer speed down to medium-low and slowly sprinkle in the sugar a little at a time, taking your time to incorporate it. After sugar is added, turn mixer speed to high and whip until very stiff, but glossy peaks form, about 6-7 minutes.
4. Remove the bowl from the mixer and gently fold in the cocoa powder, vanilla, and vinegar with a rubber spatula.
5. Mound the whipped mixture onto the parchment paper circle, piling it tall. Use a metal spatula to smooth the mound, then swipe grooves into the meringue, creating curls/swirls at the top. Gently create a fairly deep crater at the top (like a volcano, where the curls/swirls meet.
6. Turn on your oven light if you have one. Bake until the pavlova starts to turn a slightly darker brown color, about 1 hour and 15 minutes. Check after 45 minutes - if it's darkening too much, lower the oven temperature to 250° (120°C).
7. Turn off the oven after 1 hour and 15 minutes (if your oven doesn't have a light, bake it 15 minutes longer) without opening the oven and let sit for at least 2 hours(or overnight). Leaving the light on during this period will help the pavlova stay dry.
8. The center of the pavlova may collapse (that's normal) and will be where you put your filling. If it doesn't collapse into the cavity completely, use a paring knife to carefully open up a hole in the top. It may crack a little, but that's OK.
9. Run a large metal spatula under the pavlova to release it from the paper, then carefully move to a serving plate.
10. To make the Whipped Milk Chocolate Mascarpone: In a small saucepan over medium-low heat, stir together the cream, vanilla, and salt and heat until simmering. Turn off the heat and add the chocolate. Swirl the pan until the chocolate is submerged in the hot cream. Let sit for about 3 minutes, then whisk until smooth. Add the mascarpone and whisk until smooth.
11. Pour the mixture into a bowl, cover and refrigerate until chilled, at least 1 hour or up to 1 day. (It will still be runny.) It won't whip up well if it's not fully chilled.
12. Put the chilled mascarpone mixture into a stand mixer bowl and fit with the whisk attachment. Beat the mixture on medium until it just starts to thicken and turns a bit paler, about 30 seconds. Remove the bowl and continue to whip by hand, using the whisk attachment. Once the mixture is thick enough to spread, stop mixing. Use immediately.
13. For the Caramel Sauce: Off the heat, place the sugar and corn syrup into a medium saucepan, making sure not to get the sugar on the sides of the pan (or it may crystalize).
14. Add the water by gently drizzling it down the sides of the pan, washing down any sugar that may have gotten on the side of the pan. Do not stir, but gently run your (clean) finger through any dry spots of sugar, allowing the water to flow and mix into it.
15. Once the mixture is all wet, set over high heat on the stove and bring to a boil - do not stir!
16. Allow the mixture to boil until the sugar just starts to turn amber along the edges. Now you can stir without it crystalizing.
17. Continue cooking until the caramel is a medium to dark amber color (depending on how deep of flavor you want the caramel).
18. Using a long-handled whisk, carefully and slowly whisk the cream into the saucepan. The caramel with sputter and if you add the cream too fast, it may seize up. Be careful.
19. Continue to cook and stir the mixture until it melts together and becomes smooth. Add the butter and salt and whisk until smooth. Remove from the heat.
20. Let the caramel cool for 15 to 20 minutes, until it thickens. Transfer to an airtight container to store in the fridge for up to 4 days, or use immediately. If you refrigerate it, microwave it for 10-15 seconds to loosen up enough to pour.
21. Toast your nuts: preheat the oven to 350° and pour the nuts on a baking sheet - sprinkle with salt if desired. Bake the nuts for 8-10 minutes until you just get that nutty smell coming from them. Remove and set aside to cool.
22. To make the Whipped Cream: In a stand mixer bowl, add the cream, sugar, and vanilla. Beat with the whisk attachment at medium speed until just thick.
23. Remove the bowl from the stand and finish whipping by hand until the cream reaches the desired consistency (1 minute or so). Use immediately.
24. To fill: Spoon half of the chocolate mascarpone into the opening, then drizzle with one-third of the caramel sauce, sprinkle with one-third of the nuts, then top with half of the whipped cream. Repeat with the remaining mascarpone mixture, one-third more caramel sauce, one-third more nuts, and the remaining whipped cream. Finish by drizzling with the rest of the caramel sauce and sprinkle on the remaining nuts.
25. Refrigerate the pavlova for at least 1 hour before serving to make it easier to cut.