Preheat the oven to 375°F.
In a large bowl, whisk together the flour, sugar, salt, and baking powder. Cut in the butter using a pastry blender. Toss the raisins in the flour mixture.
In a small bowl or measuring cup, whisk together the buttermilk, egg, and baking soda.
Pour the wet ingredients into the dry ingredients and mix gently until just combined.
Shape the dough into a round loaf on a sheet of parchment or a greased baking sheet, and cut two deep slashes on the top in a cross shape with a sharp knife. Bake 45-50 minutes or until golden brown.