Step 1: Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with cupcake liners. In a medium bowl, whisk together flour, baking powder, baking soda, and salt — then set aside.
Step 2: In a large bowl, cream together softened butter and granulated sugar until light and fluffy (about 3–5 minutes using an electric mixer). Properly softened butter ensures a tender cupcake crumb.
Step 3: Beat in eggs one at a time, followed by vanilla extract, mixing well after each addition — this prevents the batter from curdling.
Step 4: Gradually add the dry ingredients, alternating with buttermilk, starting and ending with dry. Mix until just combined — avoid overmixing, and scrape the bowl for full incorporation.
Step 5: Fill cupcake liners about two-thirds full. Use an ice cream scoop for even portions — this gives room for rising without overflow.
Step 6: Bake for 18–20 minutes, rotating the tray halfway through. Begin checking at 18 minutes — a clean skewer in the center means they’re done.
Step 7: Cool cupcakes in the tin for a few minutes, then transfer to a wire rack to cool completely. Never frost warm cupcakes — the frosting will melt.
Step 8: In a large bowl, cream together softened butter and powdered sugar until fluffy. Add milk and vanilla, mix until smooth. Add food coloring, if desired. For a sturdier result, consider meringue buttercream.
Step 9: Frost the cooled cupcakes with prepared frosting. Decorate with sugar skulls, sprinkles, or colored icing. Use a piping bag with decorative tips for extra flair.