Preheat the oven to 350 degrees F. Generously butter two 9x5-inch bread pans. Soak the raisins in hot water for 15-20 minutes, then drain well.
Stir together the flour, sugar, baking powder, salt, and baking soda. Cut the butter into cubes and mix very thoroughly with the flour, by hand, until it looks grainy. Stir in the drained raisins and caraway seeds.
Add the buttermilk and egg to the flour mixture. Stir well. The dough should resemble thick cake batter. Equally fill 2 loaf pans. Then sprinkle the top of each with turbinado sugar to make it shimmery.
Bake for 60-70 minutes. Test with a toothpick for doneness. Cool in the pans for 3 to 5 minutes. Transfer to a wire rack to cool.
NOTE: Buttermilk can have different consistencies, depending on the brand. If your dough is thicker than dense cake batter, don't worry! Just shape it into loaves and place in the pans. No need to add more liquid.