Rhubarb puffs

Sift the flour into a large mixing bowl. Add 1 tbsp of the caster sugar, 150ml of cold water and the egg yolk, bringing it together into a paste with a wooden spoon. Knead by hand for 2 mins, then turn out onto a surface lightly dusted with flour. Roll out to make a 20cm square. Place the butter between two pieces of baking paper, then, using a rolling pin, beat into a square shape 2cm smaller than the dough square. Place the butter on top of the dough at a 90 degree angle and fold the dough edges over the butter to envelop the butter completely. Re-dust the rolling pin with flour, then roll out the pastry to a rectangle approximately 27 x 20cm. Fold one end into the middle, then the other side over it. Turn it 90 degrees, repeat rolling and folding twice, then cover in cling film and chill. After 1 hr, repeat the rolling process twice more, then cover in cling film again and return to the fridge for 30 mins. In the meantime, slice the rhubarb lengthways and cut into pieces. Place the rhubarb in a saucepan and add the cornflour and remaining caster sugar, as well as 100ml of cold water. Stir thoroughly, then bring to a simmer, stirring constantly. Simmer for 5 mins, then leave to cool. Line a tub with cling film, fill with the rhubarb mixture and freeze for 2 hrs. Preheat the oven to 200°C/gas mark 6. On a surface dusted with flour, cut the pastry into two equal pieces. Chill one piece while rolling the other out into a rectangle, big enough to cut out five squares with 20cm sides. Beat the egg in a small Makes 10 400g rhubarb, trimmed 250g strong flour, plus extra to dust 3 tbsp caster sugar 250ml cold water 1 egg yolk, plus 1 egg 250g chilled unsalted butter 2 tbsp cornflour 100g icing sugar pot, then brush the edges of each square with it. Spoon 1 tbsp of the frozen rhubarb mixture into the middle of a square. Fold one corner of the square over the filling to the other corner to make a triangle. Press the sides down to fix, then mark the ends with a fork to make a pattern. Repeat with the remaining pastry squares. Place on a greased oven tray, then repeat the process with the second piece of pastry to make five more puffs. Brush the pastries with the remaining egg wash, then bake for 15-20 mins until puffed up and golden. Allow to cool slightly before icing. In a small bowl, mix 1 tbsp of cold water with the icing sugar. Mix with a fork until it forms a thick paste. Drizzle the icing over the pastries and allow to cool before serving.