01 - Fill steamer with water and bring to a simmer. Line cupcake molds or silicone cups with paper liners.
02 - Whisk together flour, baking powder, baking soda, and salt in a bowl until well blended.
03 - Beat eggs and sugar in a large bowl until pale and thick. Add milk, melted butter, and vanilla extract. Mix thoroughly.
04 - Gradually fold dry ingredients into wet mixture until just combined. Avoid overmixing to maintain texture.
05 - Divide batter and fold in food coloring if desired. Pour batters in layers or swirl for marbled effect.
06 - Spoon batter into prepared molds, filling each about ¾ full to allow room for rising.
07 - Place molds in steamer with space between them for circulation. Cover lid with clean cloth to prevent condensation dripping. Steam over medium heat for 12–15 minutes until toothpick comes out clean and tops have bloomed.
08 - Remove from heat and let cool slightly. Decorate with sprinkles, edible flowers, or chocolate chips as desired.