Preheat the oven to 350 degrees Fahrenheit. Set aside a standard-sized muffin tin lined with paper liners.
Sift together the rice flour, brown sugar, and baking powder in a large mixing bowl. Set aside after whisking in the salt. In a medium mixing bowl, combine the coconut milk, eggs, melted butter, honey, lemon juice, and vanilla extract. Incorporate the wet ingredients into the rice flour mixture until smooth. Divide the batter evenly between the muffin cups. Sprinkle sesame seeds evenly over the tops of each muffin, then bake for 45-50 minutes, or until the tops are lightly browned and a cake tester inserted into one of the muffins comes out clean.
Cool the muffins in their tin for at least 20 minutes before removing and serving warm or at room temperature. Leftovers can be stored in an airtight container in the refrigerator for up to three days.