Place a baking sheet covered with parchment paper in the oven, and preheat to 425 F / 220 C. The oven and baking sheet should both be preheated for the best results.
In a mixing bowl, add the salt, baking powder, baking soda and sugar to the flour. Stir to incorporate the ingredients evenly.
2 ½ cups all-purpose flour, 2 tablespoons sugar, 2 teaspoon baking powder, ¼ teaspoon salt, 1 ¼ teaspoon baking soda
Add soft butter to the dry ingredients. Crumble the butter into the flour with your hands, until incorporated well.
6 tablespoons butter
Create a well in the middle of your flour mixture. Add milk. Use a dough scraper, spatula or wooden spoon, and stir to quickly combine the liquid with the dry ingredients to form a dough.
¾ cup milk
Add sultanas to the dough. Place the scones dough down on a thoroughly floured surface, and pat it down into a 2-inch or 4 cm thick patty.
½ cup sultanas
Use a dough cutter or cookie cutter to cut out scones. You should be able to cut out 4 scones from the dough. Then, reshape the unused the dough and press into a patty again. You should be able to make 8 scones in total.
Carefully place your scones on a preheated baking sheet covered with parchment paper. Optionally, brush the top of the scones with a whisked egg. This will give them a lovely golden color.
Bake for 10-15 minutes, until the scones are fluffy and golden brown.