Soak raisins in a small bowl with a splash of rum or Irish whiskey, set aside.
Mix sugar, baking powder, flour, and salt in a large bowl. Slice butter and work into dry ingredients with a spoon (do not melt butter). Add strained raisins and mix well. The mixture should be crumbly.
Make a hole in the center of the mixture and add eggs and milk. Stir with a butter knife until the mixture forms a ball and leaves the sides of the bowl.
Toss onto a well-floured surface and with floured hands, knead lightly until a soft ball is formed.
Place in a greased 9-10 inch cast iron skillet. Make a cross on the top of the loaf and brush with milk or beaten egg for extra shininess.
Sprinkle top with sugar and bake at 375°F for 10 minutes, then at 350°F for 25-30 minutes. It's done when golden brown on the top and a toothpick comes out clean.
Serve warm with butter and a cold Guinness.
Notes
The dough can be divided into two equal loaves and alternatively baked on a greased baking sheet, baked the same way.