@KarmaViolet that recipe is weirdly similar, but different. The one I used was
75g cashews
2 garlic cloves
1 tbsp tapioca flour
1.5 tsp salt
3 tsp nooch
1 tsp cider vinegar
150ml warm water
Fresh Rosemary
1 tsp olive oil
12cm ovenproof dish, lined with parchment paper
Boil cashews for 20 mins to soften. Drain and leave to cool.
Peel 1 garlic clove and blend with drained cashews, tapioca flour, salt, nooch, vinegar and warm water. Blend until smooth
Pour the cashew mix into a saucepan, taste and season with salt and pepper. Cook on a medium heat, stirring constantly, for a couple of minutes until thickened (and it thickened really quickly, so do stir from the beginning).
Pour into parchment lined dish.
Peel remaining garlic clove and cut into sticks. Gently push these and small sprigs of Rosemary into the top. Drizzle over the olive oil (realise now I forgot to do this!) and sprinkle over a little black pepper
Up to 24 hours later, when ready to cook, bake for 12-15 mins at 180C, until a skin has formed (or it looks and smells ready!) They serve theirs with garlic hedgehog tiger bread.
If it's a helpful reference, my tapioca flour was about 9 months out of date I think, and worked just fine 
@goteam your summer rolls sound lush