This recipe takes some time to prepare, but the result is really worth it – taking care not to allow the fruit to overcook. Following the timing, and your judgement carefully, the rhubarb stems stay whole yet are wonderfully tender to the bite, providing the perfect foil for a light, yoghurt style mousse.
For the yoghurt mousse
500g fromage frais
1 tblsp orange flower water
50g icing sugar
For the rhubarb and poaching liquid
400g rhubarb, peeled and cut into 10cm pieces
Place the fromage frais in a muslin-lined sieve and strain over a bowl in the fridge overnight to remove excess moisture. To prepare the poaching liquid, pour the sugar, water and grenadine into a saucepan and bring up to boiling point. Cool, transfer to a bowl and refrigerate overnight.
The next day, submerge the rhubarb in the chilled syrup, place in a noncorrosive saucepan and heat to 65C (use the sugar thermometer to check this - or your guess work will just have to be worked on!). Turn off the heat, cover with a close-fitting lid and leave for 15 minutes. Then transfer to a bowl and allow the rhubarb to cool naturally in the syrup for at least 6 hours.
Meanwhile, gently fold the fromage frais together with the remaining mousse ingredients and chill for 3 hours to set.
To serve, strain the syrup from the rhubarb into a saucepan and reduce until it clings to the back of a spoon. Allow to cool. Place two rounded spoonfuls of the yoghurt mousse in chilled bowls or glasses, spoon the pieces of rhubarb over the top and drizzle with the rhubarb syrup.