Preheat the oven to 400°F (200°C).
Mix the raisins and currants with the caraway seeds and whiskey and let soak for about 15 minutes. In a large bowl, combine the flour, sugar, baking powder, baking soda, and salt, then work in the butter until the mixture resembles a coarse meal.
Spoon the raisin-whiskey mixture quickly through the flour mixture. Beat the eggs. Reserve 2 spoonfuls of egg in a small bowl and add the rest to the buttermilk. Pour that over the flour mixture and knead until it just comes together in a ball—no longer!
Form a smooth ball of dough, lift it onto a baking sheet, and brush it with the leftover egg. With a sharp knife, carve a small cross in the middle.
Bake for 40 to 45 minutes, until the bread sounds hollow when you tap on the bottom. Let it cool on a rack.