Preheat the oven to 140°C/Fan
120°C/Gas 1. Line a large baking
sheet with baking parchment and
mark out 6 x 10cm circles (draw
around a biscuit cutter). Using
electric beaters, whisk the egg
whites to stiff peaks. Gradually
beat in 200g sugar, whisking it
back to stiff peaks after each
addition. Add the cornflour
and vinegar and whisk briefly,
until combined.
Divide the mixture between
the 6 circles on the baking
parchment, making a shallow dip
with the back of a spoon in the
middle of each. Bake for 1 hour
on the lowest shelf of the oven,
then remove and allow to cool
completely on the tray.
Meanwhile, turn the oven up to
200°C/Fan 180°C/Gas 6. Put the
rhubarb on a baking tray and sprinkle
over 2 tbsp elderflower cordial and
the remaining 45g caster sugar. Toss
together and cover with foil. Roast
for 10 minutes, until tender. Allow to
cool a little.
For the filling, use a balloon whisk
to whip the cream and remaining
80ml elderflower cordial together
to soft peaks. Divide between
the meringues, top with the
roasted rhubarb and drizzle
with the rhubarb cooking
juices to serve.