Preheat your oven to 350°F (175°C) and prepare an 8x8-inch baking pan by lining it with parchment paper and greasing it with butter.

In a large mixing bowl, crack in the eggs and combine with granulated sugar. Whisk until frothy, then add coconut milk, melted salted butter, and vanilla extract. Mix until smooth.

Gradually sift in sweet rice flour and baking powder into the wet mixture. Gently fold together until just combined to avoid overmixing.

Pour the batter into the prepared baking pan and bake for 1 hour and 25 minutes, or until golden brown and a toothpick comes out clean.

Let the mochi cool at room temperature for about 20-30 minutes before cutting into squares or rectangles.