Place coconut milk in a small saucepan over medium heat.
1 can full fat coconut milk
Mix
Meanwhile, combine sugar and cornstarch in a bowl, and add the water. whisk until completely combined.
5 Tablespoons cornstarch, 3/4 cup water, 5 Tablespoons granulated sugar
When the coconut milk just starts to simmer, add the sugar/cornstarch mix, and whisk.
Keep whisking constantly until the mixture thickens and starts looking slightly translucent. This took me about 10 minutes. When you bring your whisk up, the haupia should flow off of it and you can see the trace of it for a few seconds before it "melts away".
Set
Pour into the 8x8 pan and allow to cool on the counter before refrigerating. Refrigerate until solid and completely cooled.
Cut Into Squares & Serve
If you are using the full 5 tablespoons, you should be able to pull the sides away from the pan and invert the whole thing onto a cutting board. If it seems too soft for that, just cut it while in the pan. Cut into 2 inch pieces (16 pieces total) and serve.
Notes
Adapted from: Hawaiian ElectricI used Thai Kitchen Organic Coconut Milk, and it was a 13.66 oz can. As long as it's around 14 oz it will be fine. PLEASE make sure you are using canned coconut milk, not the drink type that comes in cartons in the refrigerated section (like Silk brand).If you want your haupia to have more of a pudding consistency, use less cornstarch. You can try 4 tablespoons, or if you want it even less firm, try 3!