Preheat your oven to 350°F (175°C). Grease a 9-cup muffin tin with non-stick spray or softened butter.

In a medium saucepan, heat the full-fat coconut milk over medium heat until it begins to boil, about 5 minutes.

Once boiling, add the Thai tea leaves and stir for one minute, then remove from heat and let steep for 7 minutes.

In a mixing bowl, whisk together mochiko rice flour, dark brown sugar, baking powder, and a pinch of salt.

Strain the tea leaves from the coconut milk. Combine the strained milk with the egg, vanilla extract, and melted butter in a large bowl.

Gradually mix the dry ingredients into the wet mixture until just combined, taking care not to over-mix.

Pour the batter into the muffin tin, filling each cup about ¼ inch from the top. Sprinkle sesame seeds on top.

Bake for 55-65 minutes until tops are crisp and a knife comes out clean. Let cool in tin for 5-10 minutes.

Transfer to a wire rack to cool completely before serving.