Preheat your oven to 375°F (190°C). Grease a 12-count muffin tin lightly with butter or cooking spray. This helps the muffins come out easily after baking.

In a large bowl, add flour, sugar, baking soda, baking powder and salt. Whisk everything together until well combined. This ensures even texture in every muffin.

Add cold butter cubes to the flour mixture. Use your fingers or a pastry cutter. Mix until the mixture looks like coarse crumbs with small butter pieces.

Add raisins into the dry mixture. Toss gently so raisins are coated with flour. This prevents them from sinking to the bottom during baking.

In another bowl, whisk buttermilk and egg together. Mix until smooth. The buttermilk gives softness and classic soda bread flavor.

Pour the wet mixture into the dry ingredients. Stir gently with a spatula. Mix just until combined. Do not overmix or muffins will become dense.

Scoop the batter evenly into the muffin tin. Fill each cup about three-quarters full. Smooth the tops lightly with the back of a spoon.

Place the muffin tin in the oven. Bake for 16 to 18 minutes. The tops should turn golden brown. Insert a toothpick in the center to check doneness.

Remove muffins from the oven. Let them cool in the pan for 5 minutes. Then transfer to a wire rack. Serve warm for best taste.