Step 1Heat the oven to 350 degrees. Place the pistachios on a baking sheet and toast until just lightly golden, 8 to 10 minutes. Set aside.
Step 2Carefully rinse the strawberries, blueberries, blackberries and raspberries. Hull and halve the strawberries. Place berries into a bowl with the sugar and vinegar. Set aside to macerate for 30 minutes.
Step 3Pour the cold whipping cream into a large bowl (or the bowl of a standing mixer if using). Scrape the seeds from the vanilla bean into the cream. Using a standing mixer fitted with the whisk attachment, a handheld mixer or a balloon whisk, whisk the cream until soft peaks form, about 2 minutes. Chill until ready for assembly.
Step 4When ready to assemble, place the cooled Pavlova shell onto a large platter. Mound the whipped cream in the center, then spoon the macerated berries over the cream. Crush the pistachios slightly (using a rolling pan or heavy pot); sprinkle the pistachios over top. Cut into slices at the table.