01 - Preheat oven to 350°F. Line a 12-cup muffin tin with paper liners or grease lightly.
02 - In a large mixing bowl, whisk together sweet rice flour, granulated sugar, baking powder, and salt until thoroughly blended.
03 - In a separate bowl, whisk whole milk, eggs, melted butter, ube halaya, and vanilla extract until smooth and fully incorporated.
04 - Pour wet mixture into dry ingredients. Mix gently until just combined, avoiding overmixing.
05 - Fold dried cranberries into the batter, distributing evenly.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full. Sprinkle unsweetened coconut flakes on top if desired.
07 - Bake for 32 to 36 minutes, or until the muffins are set and tops spring back when gently pressed.
08 - Let muffins cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before serving.