Preheat the oven to 220 C | 425 F and line a baking sheet with parchment paper.
In a mixing bowl, whisk together the flour, sugar, baking powder, baking soda, and salt. Grate the butter and mix well into the flour mixture until the mixture resembles coarse meal. Place the bowl in freezer for 5 minutes.
In a large measuring cup, whisk together the cold buttermilk and egg.
Stir in the golden raisins in the flour mixture. Add the buttermilk-egg mixture and using a spatula mix until combined.
Transfer the dough to a lightly floured surface and knead for 4-5 minutes.
Pat the dough gently with your hands into a disc that is roughly 3/4-inch thick. Using a cookie cutter, cut out the scones.
Place them on the prepared baking tray and brush the tops gently with milk.
Bake for 10-12 minutes or until tops are golden brown. Transfer scones to a wire rack.