Preheat Oven and Prep Pan:

Set oven to 400°F (205°C). Insert paper liners into a standard 12-cup muffin pan. Alternatively, thoroughly coat the wells and pan top with non-stick spray or butter.

Mix Dry Ingredients:

In a large bowl, combine flour, baking powder, baking soda, salt, sugar, and raisins using a whisk.

Whisk Wet Ingredients:

In a separate small bowl or measuring cup, whisk egg, buttermilk, and melted butter together.

Combine Wet and Dry:

Add the wet mixture to the dry mixture. Using a wooden spoon or spatula, stir only until no flour remains visible. Avoid overmixing to ensure tender muffins; the batter will be thick.

Fill Muffin Cups:

Evenly distribute batter among the prepared cups, filling each about 3/4 full. The batter will dome slightly. Top each with sparkling sugar.

Bake and Cool:

Bake for 18–20 minutes, until a cake tester inserted in the center comes out clean. Remove from oven. Tilt muffins in the pan to prevent soggy bottoms. After 5 minutes, move to a wire rack to cool completely.