Preheat oven to 350 degrees F. Line a 9x9" cake pan with parchment paper.
Pour the 1 cup of black sesame seeds into a food processor and finely grind them.
In a large mixing bowl, combine eggs, sugar, and coconut oil. Then, add the coconut milk and evaporated milk and mix it in. Lastly, add the sweet rice flour, baking powder, and salt through a sieve into the mixture, and whisk it all together until smooth.
Pour the batter into the cake pan. In a small bowl, mix together the black and white sesame seeds, then sprinkle them on top of the batter.
Put the pan into the oven for 70 minutes. Once done, let it cool in the pan for an hour, then transfer to a wire rack for at least another 30 minutes.
Cut into pieces and enjoy!
