Ingredients

• 2 lb Okinawan Sweet Potatoes
• ½ cup unsalted Butter, at room temperature
• ¾ cup Sugar
• 2 Eggs
• ½ cup Whole Milk
• 1 tsp Vanilla Extract
• ¼ tsp Kosher Salt

• 2 cups Bob's Red Mill Organic Unbleached All Purpose White Flour
• ½ cup Sugar
• 1 cup cold unsalted Butter, cut into ½-inch cubes
• ¾ cup salted dry-roasted Macadamia Nuts, coarsely chopped

• ⅔ Sugar
• ¼ tsp Kosher Salt
• ½ cup Cornstarch
• 3 cups full-fat canned Coconut Milk
• 1 ⅓ cups Whole Milk

Instructions

1. Preheat the oven to 350°F and line a baking sheet with parchment paper. Everything will be baked at this temperature, so keep the oven on throughout. Begin by baking the sweet potatoes. Prick the sweet potatoes all over with a fork, at least five times on each potato. Set them on the prepared baking sheet and bake for 40 minutes-1 hour, depending on the size of the potatoes. Start checking the doneness after 35 minutes. To check if they are done, simply insert a fork into the middle of the potato; if it goes in easily with little resistance, it’s done. Set the baked potatoes on a wire rack to cool. When cool enough to handle, peel off the skins from the potatoes and cut them into 1-inch cubes. Transfer the cubes to the bowl of a stand mixer fitted with the paddle attachment and beat on medium speed for 1-2 minutes, until smooth and fluffy; you should have about 2 cups. Remove from the bowl, cover and set aside.
2. Meanwhile, make the shortbread layer. In a large bowl, combine the flour and sugar and give it a quick mix with a wooden spoon or your hands. Using a pastry blender, cut the cold unsalted butter into the flour mixture, blending until the mixture resembles coarse sand. If you don’t have a pastry blender, you can combine the sugar and butter in a food processor and pulse until the butter is pea size; add the flour and pulse until it resembles coarse sand. Add the macadamia nuts and mix with a wooden spoon or your hands. Press the mixture into a 9 x 13-inch baking pan and prick with a fork ten to fifteen times all over the surface. Bake until the crust is golden brown, 15-20 minutes. Set the pan on a wire rack to cool.
3. To make the sweet potato layer, in a large bowl, combine the room-temperature butter and ¾ cup of the sugar and beat with a hand mixer on medium-low speed. Add the eggs, one at a time, mixing on low to incorporate. Add the sweet potatoes and mix on medium-low until thoroughly combined. Add the milk, vanilla, and salt, mixing on low until well combined. Pour the mixture over the baked crust and bake until the potato has set and has a pale golden tone on top, 30-35 minutes. Turn off the oven. Set the pan on a wire rack and let the potato layer cool for at least 30 minutes before making the haupia layer.

1. In a medium saucepan, combine the sugar, salt and cornstarch. Whisk in the coconut milk and set the pan over medium-high heat. Whisk continuously until the mixture starts to simmer. Immediately turn the heat down to medium-low and continue to whisk continuously until the mixture begins to thicken, 4-6 minutes. The mixture will go from liquid to very liquid before it starts to thicken.
2. Pour in the whole milk in a steady stream while continuing to whisk. Bring the heat back up to medium and continue whisking until the mixture has thickened to the consistency of a thick glue and can coat the back of a spoon, another 4-6 minutes.
3. Pour the haupia over the top of the cooled potato layer and let cool for 10 minutes. Cover with plastic wrap and transfer the pan to the refrigerator to chill and set for at least 2 hours. For an extra-smooth top, carefully place a sheet of plastic wrap directly on the top of the haupia after it has cooled for 10 minutes. When chilled, slice the bars into rectangles; I usually cut four columns and seven rows.