Preheat the oven to 325?F.
In a medium saucepan, combine the cranberries, sugar and orange juice over medium-high heat. Bring to a boil, reduce the heat and cook, stirring occasionally, until the berries begin to pop and the sauce thickens. Transfer to a bowl and refrigerate until chilled. (You can do this part up to 3 days ahead.)
To make the meringue, put the egg whites in the clean stainless steel bowl of your Oster® Brand stand mixer with the whisk attachment and in a small bowl or measuring cup, stir together the sugar and cornstarch to get rid of any lumps. Beat the egg whites until they’re foamy, and the whisk starts leaving a trail through the whites. Add the sugar mixture gradually, beating on high speed until the sugar is all incorporated and the whites are stiff and glossy. Beat in the vinegar and vanilla.
Spread into a parchment-lined 9x13-inch pan and bake for 30 minutes, or until puffed, pale golden and set. Invert onto another piece of parchment (or a clean tea towel) that has been sprinkled with icing sugar and peel the parchment off the bottom of the meringue. Meanwhile, beat the cream and icing sugar until it holds soft peaks.
Spread the whipped cream over the meringue and drop spoonfuls of cranberries over the cream, reserving a few spoonfuls to dribble overtop if you like. Starting at a short end, quickly and gently roll the meringue into a log—don’t worry if it cracks—and transfer to a serving platter. Top with icing sugar, grated white chocolate and the reserved cranberry sauce, if you like. Serves 8.