Preheat the oven to 350°F (175°C) and grease an 8×8 inch baking pan.
In a large bowl, combine mochiko flour, sugar, baking powder, and salt. Mix well.
In another bowl, whisk together poi, coconut milk, eggs, and vanilla extract until smooth.
Slowly add the wet ingredients into the dry mixture. Stir until a thick, smooth batter forms.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 50–60 minutes, or until the top is lightly golden and the center is set.
Allow the poi mochi to cool completely before slicing. Cooling helps develop the soft, chewy texture.
Cut into small squares and serve at room temperature.