Heat the blueberry jam on a low-med heat for a few minutes then strain through a sieve to discard the solids. Leave to cool.
Line 1-2 baking trays with baking paper – crumple the paper first as this makes it sit on the tray more firmly.
Using a glass or metal bowl, whisk the chickpea water with an electric whisk until it starts to turn white and frothy. Add the cream of tartar and whisk in.
Add the sugar, a tablespoon at a time and whisk until it is glossy and stiff. Depending how powerful your mixer is, this can take from 10-20 minutes. You should be able to turn the bowl upside down without the meringue fluff falling out.
Midway through the beating, pre-heat your oven to 100°C/200°F/just under Gas Mark ¼.
Transfer the stiff meringue mixture to a piping bag and pipe around 6 large dollops onto baking paper on a baking tray.
Make an indentation in the centre of each meringue to hold the filling.
Using the sieved blueberry jam, create a zigzag pattern over the meringues before putting into the oven.
Bake for two hours then turn off the oven. Unclick the door and leave to cool for an hour before taking out. Gently peel away from paper. Once they’re cooled, store in an airtight container until the dessert is assembled.