Towering Pavlova

Preheat oven to 300°. Line a baking sheet with parchment paper. Trace a 6-inch circle on the paper and flip it over; set aside.

Prepare meringue: In a large bowl (or the bowl of a stand mixer), beat egg whites and a pinch of salt with an electric mixer on medium-high speed until medium-stiff peaks form. Reduce speed to low; drizzle in the cold water. Gradually beat in the superfine sugar, adding it just a bit at a time. Crank the speed to high; beat until stiff peaks form. (When you pull the beaters from the mixture, the meringue should stand up straight in a point, without curling at the tip. Another good test: Hold the bowl upside-down; the mixture shouldn't budge.) Fold in 1 teaspoon each white vinegar and vanilla. Sift in the cornstarch; fold in gently.

Mound the meringue onto the circle you drew. Gently shape the sides using an offset or silicone spatula. (To re-create Zoë's pumpkin-like ridged dome, drag an offset spatula upward with a flick at the end, then repeat, working your way around.) Create a very slight dip in the top.

Bake on the center oven rack until the meringue starts to turn a very pale tan, about 30 minutes, then reduce heat to 275° and continue to bake for 45 minutes. Turn off the oven (don't open the door), turn on the oven light, and let the meringue rest for at least an hour, ideally several (or overnight). If it's humid, plan to store the pavlova in the oven (without opening the door), right up until serving.

To assemble: In a chilled large bowl, beat whipping cream, powdered sugar and the remaining 1 teaspoon vanilla on medium speed until stiff peaks form. In a small bowl, stir the lemon curd until smooth. Slide a knife or offset spatula under the meringue to loosen it before peeling off the paper. Transfer to a plate. Fill with whipped cream, lemon curd, passion fruit and raspberries. Dust with powdered sugar and serve immediately.