Preheat the oven to 140°C/fan 120°C/gas mark 1. Line a large baking sheet with baking paper.
In a large clean bowl whisk the liquid from the chickpeas with the cream of tartar until it forms stiff peaks using an electric hand whisk. This will take longer than whisking egg whites.
Once stiff, gradually add the caster sugar, a spoonful at a time, and continue to whisk until glossy and firm for around 10-15 minutes.
Spoon 6 blobs of mix on to the baking paper and bake in the oven for 1 hour. Turn the oven off, leave it ajar and leave the meringues to cool in the oven.
Make the coconut cream by spooning the firm coconut milk out of the tin into a bowl, leaving the liquid behind. Add the icing sugar and vanilla extract, and whisk until soft speaks form.
Top the cooled meringue with the coconut cream, blackberries and chopped chocolate.