Makes 18 × 17g biscuits
Ingredients for the rhubarb stock syrup:
500g rhubarb
1 litre water
250g caster sugar
Ingredients for the rhubarb pieces:
300g rhubarb
50g caster sugar
400ml rhubarb stock syrup (see above)
Ingredients for the blackberry preserve:
250g blackberries
80g caster sugar
2g pectin
125ml water
10ml lemon juice
Ingredients for the blood and pistachio biscuits:
50g fresh pork blood
120g caster sugar
110g ground almonds
90g ground pistachios
4g finely chopped pistachio per biscuit, to coat
icing (confectioners’) sugar, to dust
Method
For the rhubarb stock syrup
Roughly chop the rhubarb and combine it with the water and sugar in a vacuum pack. Steam for 20 minutes. Remove the ingredients from the vacuum bag, strain away the solids and chill the liquid.
For the rhubarb pieces
Peel the rhubarb and place it in a saucepan with the sugar sprinkled evenly over the top. Leave to stand for 30 minutes or so, then gently warm the pan, dissolving the sugar and steaming the rhubarb to al dente.
Remove the rhubarb and leave it to cool. Deglaze the pan with the rhubarb stock syrup and reduce it to 100ml. Reserve the rhubarb glaze in a piping (pastry) bag. Cut the rhubarb into even 1.5cm pieces that will fill the centre of the biscuits.
For the blackberry preserve
Combine all the ingredients in a saucepan and cook to 108ºC (226ºF). Process to a fine purée and leave to cool and set. Reserve in a piping (pastry) bag.
For the biscuits
Preheat an oven to 170ºC (338ºF).
Combine the blood, caster sugar and ground nuts and process together to form a paste. Roll the mixture into 17g balls, coat with the finely chopped pistachio and then shape them into small biscuits, about 2.5cm across. Make a little indentation in the top of each biscuit and fill each of these with first with a little blackberry preserve, then a piece of rhubarb.
Bake the biscuits for exactly 13 minutes. Remove the biscuits, dust them with icing sugar and then dab a little rhubarb stock syrup over each piece of the rhubarb.
Leave to cool.