Preheat your oven to 350°F (175°C). Gather your ingredients.

In a medium mixing bowl, combine mochiko flour, granulated sugar, and baking powder. Whisk until well-blended.

In a large bowl, whisk together water, coconut milk, and vanilla extract until smooth. Add food coloring if desired.

Gradually add the dry mixture to the wet ingredients, stirring until smooth.

Prepare a 9x13 inch baking pan with non-stick cooking spray. Pour the batter into the pan.

Cover the pan tightly with aluminum foil and bake for about 60 minutes.

Remove from the oven and let cool completely at room temperature.

Dust a clean surface with potato starch, invert the mochi onto it, and cut into bite-sized pieces.

Serve fresh at room temperature or store leftovers in an airtight container.