Preheat the oven to 350 degrees F. Arrange the oven rack to the middle row. Line a baking sheet with parchment paper.
Add the flour, sugar, baking soda and salt to a large bowl and whisk to blend. Toss in the butter and cut in using a fork until it looks like little pebbles. Add in the caraway seeds, 1 1/4 cup buttermilk and the raisins and stir until it looks like a dry biscuit dough. Knead for 1 minute or so until the dough comes together.
Form into a 7-inch diameter round ball and place on the prepared baking sheet. Brush the round with the remaining buttermilk, and then score an X on the top of the round using a sharp knife.
Bake until golden brown and when a wooden skewer inserted into the center of the loaf comes out clean, about 1 hour 10 minutes. Let cool on a wire rack before slicing.