The last time I used these magical things were in my purple sweet potato roll cake last year. I love the rich flavour of them compared to the regular kind found in the supermarket, but alas, they only seem available for a few months a year in one store in Chinatown, it seems.
What's haupia? Haupia's the white layer of this pie, and is essentially a rich set coconut custard. It's a Hawaiian dessert and often eaten by itself like a jelly, but here the flavours work with the sweet potato incredibly well.
Anyway! Onto the recipe. This recipe can be found on numerous sites on the interweb... but all of them leave you with lots of leftover sweet potato mixture, and- a little more suspiciously- none of them actually used the given pastry recipe, instead opting to use a ready-made crust. The crust sounded delicious- a sort of sweet shortcrust with macadamia nuts. Why was no-one making it?
My pie didn't start off with strikingly stripy bare sides to begin with: originally I lined the pie tin so the pie would have a fluted crust around the side, too. The recipe said to pack the crust into the pie tin like you might for a cheesecake, but even following the recipe 100% yielded a soft pastry, rather than a crumb. The other significant problem was that the recipe made a crust that was far, far too crumbly after baking to remain structurally sound around the sides... resulting in crumbling walls. And this happening.
I may have chopped the macadamia nuts too finely, in hindsight- mac nuts are really high in oil content.
I wasn't too bothered though- I'd taken a risk in my approach and had learned something- and once I'd neatly removed the remaining pastry ruins and cleaned up the edges, I had a bowl of really tasty macadamia shortcrust cookies to snack on. Accidentally prettier pie, extra snacks, everybody wins!
So. Here is the same recipe that everyone else uses (with just one or two of my own tweeks)-but also, here's how to do it right to get one neat pie.
Ingredients for Crust:
-85g unsalted butter, softened
-1tbsp caster sugar
-110g plain flour
- 50g finely chopped macademia nuts
-Pinch of salt
Ingredients for Sweet Potato Layer:
-60g unsalted butter, softened
-130g boiled/ steamed and mashed sweet potato (any will do, but purple is my favourite!)
-75ml evaporated milk
-Pinch of salt
Ingredients for Haupia Layer:
-1 can coconut milk
-70g caster sugar
-1 pandan leaf (optional- I just love pandan with coconut)
1) Preheat the oven to 180 degrees C, and lightly grease an 8" pie dish
2) Stir all of the crust ingredients together until it forms a dough, and pack evenly into the bottom of your pie dish (if you want to be precise about it, wrap the dough up in clingfilm and put it in the fridge for half an hour to firm up so you can roll it out)
3) Make the sweet potato layer next: cream the butter and sugar together, and whisk in the eggs. Now whisk in everything else, and pour over the crust (it should only fill the tin halfway, giving you room for the haupia layer later)
|(You won't have crust around the sides for this recipe)|
4) Bake for 30-40 minutes, or until the sweet potato layer is *just* beginning to brown at the edges and the middle is set. Now you have to wait for the pie to cool completely before making the haupia
5) Put the cornflour and sugar into a small saucepan, and gradually sir in the water with a balloon whisk so you form a loose paste. Now stir in the coconut milk, pop in a knotted pandan leaf (if you have one) and turn the heat up to medium
6) Keep stirring with your whisk until the haupia gets really really thick (remove the pandan leaf when it just starts to thicken)
7) Pour the thickened haupia straight onto the cooled pie and smooth the surface
8) Wait an hour or so for everything to cool down again, slice, serve and enjoy!