How to Make It
Preheat the oven to 275°. Grease an 8-inch square glass pan. In a medium bowl, whisk together the rice flour, sugar, baking powder and matcha powder. In a separate bowl, whisk together the water, coconut milk and vanilla extract. Pour the wet ingredients into the dry ingredients and whisk until smooth. Pour the batter into the pan, cover tightly with foil and bake for 60-80 minutes, until the top is set. Remove the foil, let it cool and then recover with foil and let it sit at room temperature overnight.
Turn the mochi onto a cutting board and cut small cubes with a sharp knife. Coat all over with cornstarch.