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–+ servings

Okinawan Purple Sweet Potato Haupia Pie Bars

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Sweet potato haupia pie is a classic local Hawaii style dessert. I like to make mine with a graham cracker crust, but traditionally it would use pie or shortbread crust (see notes). This recipe is meant for an 8x8" pan, but you can easily double it for a 9x13" dish.
Course Dessert
Cuisine Hawaiian
Prep Time 15 minutes
Cook Time 40 minutes
Cooling Time 1 hour
Total Time 1 hour 55 minutes
Servings 16 pieces
Author Mochi Mommy

Equipment

  • 8x8" metal baking pan

Ingredients

For Graham Cracker Crust

  • 1 1/4 cup graham cracker crumbs
  • 5 tbsp melted butter
  • 1 pinch salt

For Sweet Potato Filling

  • 1 cup purple sweet potato puree 180g, from about 1-2 sweet potatoes
  • 6 tbsp sugar
  • 1 egg
  • 1/4 cup heavy cream or half and half
  • 1 pinch cardamom optional
  • 3 tbsp melted butter
  • 1 tsp vanilla extract

For Haupia

  • 1 12 oz can coconut milk
  • 3 tbsp sugar
  • 3 tbsp cornstarch
  • 1/4 cup water

Instructions

Make the Graham Cracker Crust

  • Preheat oven to 350 degrees F.
  • Mix graham cracker crumbs, butter, and salt
  • Press crumbs firmly onto the bottom of a greased 8x8" square baking pan
  • Bake in the oven for 10 minutes while you prepare the sweet potato filling.

Purple Sweet Potato Filling

  • Cook your sweet potatoes to make a puree: you can do this in the microwave, in the oven, or by boiling - however you would normally make a baked or roast potato. I typically use the microwave: poke holes in your sweet potatoes with a fork, cover, and microwave for 6-7 minutes or until you can very easily pierce through the sweet potato. Peel the skin off the potatoes and mash the insides. You can do this a few days ahead of time and save the puree in the fridge.
  • Take one cup of sweet potato puree and mix with the sugar, egg, heavy cream, cardamom, melted butter, and vanilla extract.
  • Spread the filling over the graham cracker crust. It will be a thin layer.
  • Bake until set - about 20 minutes, or until a toothpick poked in the center comes out clean. Then set your pie to cool in the fridge.

For the Haupia

  • While your baked sweet potato layer is cooling, make the haupia.
  • Mix sugar, cornstarch, and water in a separate bowl to make a slurry.
  • Pour can of coconut milk in a pot and heat on stovetop.
  • When the coconut milk is just starting to bubble, pour in your cornstarch slurry very slowly while continuously whisking the hot coconut milk in the pot. It's important to keep stirring to avoid lumps.
  • Cook the haupia, continuously whisking, until the mixture has thickened to a pudding like consistency. Do not let the mixture boil, but a few bubbles are okay.
  • Take the haupia off the heat. Then, very gently spread over the purple sweet potato filling.
  • Place the pie into the fridge to let the haupia layer set. I like to leave it uncovered in the fridge until the top has become dry to the touch, then I cover with plastic wrap.
  • When the pie has fully cooled and the haupia is set, you can cut it into squares to serve.

Notes

  • You can double the sweet potato portion of the filling if you like extra thick pie bars and lots of sweet potato. The photos in this post reflect a single portion of the filling. My Instagram video of me making this recipe uses a double portion.
  • If you can't find Okinawan sweet potato or they're too expensive, you can use Molokai sweet potato, which is purple on the outside and inside. The Stokes sweet potatoes brand are an example of a Molokai sweet potato.
  • You can also make this recipe in a 9x9" square baking dish, although the layers will be slightly thinner.
  • If you would like to use a macadamia nut shortbread crust, you can find my recipe in my post for the standard round pie version of this recipe.