3 free-range egg whites
1⁄2 tsp cream of tartar
185g golden caster sugar
2 Tbsp dark brown sugar
150g 70% dark chocolate, chopped
1⁄4 cup smooth peanut butter
1⁄2 cup cream
1 tsp natural vanilla extract
1 bunch rhubarb, trimmed
Finely grated zest of 1 orange 4 sage leaves
1 vanilla bean, split lengthways, seeds scrapped
1⁄2 cup caster sugar
1 Tbsp balsamic vinegar
White chocolate bark (see Cook’s tip, below), to serve
Freeze-dried strawberry slices, pistachios and dried rose petals (optional), to decorate
Preheat oven to 110°C fan-forced (130°C conventional). Line 2 large oven trays with baking paper. Put egg whites, cream of tartar and golden caster sugar in the bowl of an electric mixer and stir well. Set over a saucepan of barely simmering water and heat until sugar dissolves. Put bowl in mixer and beat on high, using whisk attachment, for 5 minutes or until thick and glossy.
Scatter over brown sugar, fold in gently, then spoon egg white mixture into a piping bag (without a nozzle). Pipe onto prepared trays to make 16 round peaks 7cm wide. Bake for 4 hours or until crisp. Remove from oven.
Meanwhile, combine chocolate and peanut butter in a medium bowl. Put cream and vanilla in a small saucepan over a medium heat and bring to a simmer. Pour hot cream mixture over chocolate mixture and whisk until smooth. Set aside ganache to cool.
Increase oven temperature to 180°C. Cut rhubarb into 6cm lengths and put in a medium bowl. Use a mortar and pestle to pound orange zest, sage leaves, vanilla bean seeds and caster sugar until smooth, then toss with rhubarb. Arrange rhubarb mixture in a baking dish and drizzle with balsamic. Cover dish with a sheet of slightly dampened baking paper and bake for 20 minutes or until rhubarb is just tender. Allow to cool.
Spread flat-side of a meringue disc with a little ganache and sandwich with another disc. Repeat to sandwich all meringues.
Serve meringues with rhubarb and a shard of choc bark decorated with strawberries, pistachios and petals, if using.