Preheat the oven to 425 degrees F. Line a baking sheet with parchment; set aside.
In a large mixing bowl, whisk together the all-purpose flour, sugar, salt and baking soda. Using a box grater, grate the butter into the dry ingredients and mix quickly, breaking up the butter so it's broken up into pea-sized bits throughout. Next, add the currants and toss them gently in the flour mixture so they are evenly distributed.
Create a well in the center of the flour mixture and pour in the buttermilk. Using a wooden spoon, mix it together until it forms a shaggy ball. Drop the soda bread dough onto a lightly floured counter and knead a few times, being sure to not over handle it, which will result in tough bread. Form the soda bread into a 1 1/2-inch thick disc. Using a knife, cut the scones into 6 equal triangles. Form the triangles into circular shaped scones (or leave them as is, if you like). Transfer the scones to the baking sheet and put in the freezer to chill for 5 to 10 minutes. Using a knife, score the tops, forming an X; brush the tops with buttermilk and sprinkle each scone with a pinch of salt.
Transfer the soda bread scones to the oven and bake for 25 to 30 minutes, until a skewer inserted into the centers comes out clean and the scones are golden brown. Serve warm with salty whisky butter.
Salty Whiskey Butter: To make the butter, add the whisky to a small saucepan, cook for a few minutes, until it begins to simmer slightly and it decreases to about 2 tablespoons Irish whiskey. We really just want to cook some of the alcohol out. Allow the whisky to cool completely. To a small bowl, add the softened butter, powdered sugar, cooled Irish whiskey and salt. Using a hand mixer (I only used one of the beaters!), beat until fluffy.