01 - Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners or lightly grease each cup.
02 - In a large mixing bowl, whisk together sweet rice flour, granulated sugar, baking powder, and salt until evenly blended.
03 - In a separate bowl, whisk together whole milk, eggs, melted unsalted butter, ube halaya or puree, and vanilla extract until the mixture is completely smooth.
04 - Pour the wet mixture into the dry ingredients. Gently mix just until combined, being careful not to overmix for optimal texture.
05 - Carefully fold in dried cranberries, distributing them evenly throughout the batter.
06 - Divide batter evenly among muffin cups, filling each about three-quarters full. Sprinkle unsweetened coconut flakes over the tops, if desired.
07 - Bake for 32 to 36 minutes, or until the muffins are set and the tops spring back when gently pressed.
08 - Allow muffins to cool in the tin for 10 minutes, then transfer to a wire rack to cool completely before serving.