Preheat the oven to 200F/93C. Line a large baking sheet with parchment paper and draw a 6-inch (15-cm) circle on the back to use as a rough guide.
Place the egg whites into a stand mixer bowl and add the cream of tartar, cornstarch, vanilla extract and lemon juice. Whisk everything together for about 30 seconds on medium speed.
Set the mixer to medium speed and begin adding the fine sugar, 1 tablespoon at a time; this will take about 10 minutes. Stop occasionally to scrap down the sides of the mixing bowl any sugar that may get attached to the sides.
Once you’ve added all the sugar, continue to whisk the meringue on medium speed for 15 to 20 minutes, until the sugar is completely dissolved. Rub a small amount between two fingers to check the meringue. When it’s no longer grainy, it’s ready.
Transfer the meringue into a pastry bag tipped with a large tip; I usually have to do this twice since there’s quite a bit of meringue! Pipe the prepared meringue onto the prepared baking sheet in a circle, then build it up into a tall wreath. Watch my video tutorial to see how I do it. Use a spoon to smooth the sides and top of the meringue, then flatten the top just a bit, to have room for the whipped cream and berries.
Bake the pavlova at 200F/93C for 1 ½ hours, then turn the oven off and let it cool slowly in the oven for 3 to 4 hours. Do not open the oven at any point!!
Once the pavlova has cooled, removed it from the oven and keep it at room temperature until you’re ready to assemble the dessert.
Making Raspberry Sauce:
Start with fresh or frozen raspberries. Place the raspberries and the sugar into a medium-sized saucepan and mash the berries together. Cook over medium heat, until the berries come up to a simmer. Simmer for 4 to 7 minutes, until a thick jam forms.
Transfer the jam into a fine mesh strainer setup over a bowl or tray. Using a spatula, press the sauce through the sieve, leaving behind the seeds. Discard the seeds and place the resulting sauce into the refrigerated to cool.
Making Whipped Cream:
Soften the mascarpone cheese at room temperature for about 15 minutes. Don’t let it sit out for too long, otherwise it can separate. Place the mascarpone cheese, vanilla, confectioner’s sugar and chilled heavy cream into a large mixing bowl.
Whisk all the ingredients together for 4 to 5minutes, starting out on slow speed, until stiff peaks form. Keep this whipped cream refrigerated until you’re ready to assemble the dessert. I recommend making it the same day.
Assembling the Pavlova:
Once the pavlova has cooled, keep it at room temperature until you’re ready to assemble it. I recommend assembling it shortly before you serve it, so that the outside of the pavlova stays crunchy!
Place the prepared whipped cream into a pastry bag tipped with a star tip; I used Ateco #847. Place the pavlova wreath onto a cake stand or tray, then pipe the whipped cream over the top.
Add spoonful’s of the prepared raspberry sauce over the whipped cream. Save some of the sauce for serving on the side.
Garnish the top with raspberries, strawberries and/or pomegranate arils. Serve the pavlova as soon as possible. Refrigerate any leftovers to prevent the whipped cream from melting.