Prawnish Crackers
Prawn crackers in regular and wasabi flavour!

There seems to be only one recipe for prawn crackers in the world. Well, almost.
So you'd think it would be hard to go wrong, but I must say I really struggled to get my crackers to puff up the way I wanted them to. It seemed I'd cut them thinly enough - since they weren't really coming out too fat, just not as fluffed as I'd hoped. I was finally getting my prawn crackers to expand by raising the temperature of the oil quite a bit from the suggested 350°F - up to more like 370-380°F, when they start to swell reassuringly, or up around 400°F when they really get going. since the smoke point of sunflower and peanut oil are up around 450°F/230°C you could go still higher! Giving them a few prods as they start swelling seems to help them along, but you need to scoop the crisps out of the oil just as soon as they float to the surface or they'll immediately start to burn.

Curiously my wasabi-flavoured crisps just wouldn't puff up effectively at all - even at the higher temperature, though they tasted quite promising. Given that they were exactly the same recipe, just with the wasabi added, it's hard to see why not, possibly my original mixture was too wet, possibly I could try using wasabi powder rather than paste, but I definitely need to work on them before they're ready for prime time!
It does look like the pungent oils in horseradish (and presumably by extension, wasabi) are destroyed, or greatly diminished, by cooking. Which makes it look like my concept of wasabi-flavoured prawn crackers is a bust.
Perhaps mustard could be used as a reasonable substitute?

Here are some ideas for improving your cracker puffing experience I've seen on t'intertubes:

Prawn Crackers - Ish
starter fish
Oh and I bought my dehydrator just for this!

Makes a dehydrator-load: Enough for 4-6

Ingredients
Method
Peel and de-vein the prawns (or shrimp) and blend in a food processor to a smooth paste with the wasabi paste (if using). Remove to a mixing bowl, add the tapioca flour and salt, pepper, MSG and sugar (if using). Knead by hand or with a dough hook until the dough is smooth and not sticky. You may need to start things off by hand in any case, and you also might need to add a little water to get this going, but be warned - a little water goes a long way!
Roll the dough into a nice log shape, get your steamer going, then put the log on a greased plate or piece of foil in the basket, Or banana leaves! If you have any banana leaves. It seems you can also cover them so they don't get too wet and dripped on if you like, but that doesn't seem essential. and steam over a high heat for 35-60 minutes.

So, I wasn't entirely sure about the wasabi, so I made an 8oz (of prawn) quantity and divided it in two - one half taking 2 tablespoons of wasabi paste (and a couple more teaspoons of wasabi powder ... and more tapioca flour), then rolling each half into a log and steaming for 45 minutes.
I then cut them as thinly as I could manage (though I didn't bother freezing the logs to stiffen them - they're surprisingly firm as is though) and completely filled my dehydrator with them. I dried them for 12 hours at 70°C.

It's worth bearing in mind that the wasabi you'll be using isn't wasabi at all - it's various kinds of mustard. So some of its flavours ought to survive the cooking process :)