01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper or lightly grease it.
02 - In a large bowl, whisk together the flour, sugar, baking soda, and salt until well blended.
03 - In a separate bowl, whisk the buttermilk, egg, and melted butter until fully combined.
04 - Pour the wet ingredients into the dry mixture. Add the raisins and orange zest. Stir with a wooden spoon until a shaggy dough forms.
05 - Turn the dough onto a lightly floured surface. Knead gently just until it comes together, being careful not to overwork. Shape into a round loaf about 7 inches across and place on the prepared baking sheet.
06 - Using a sharp knife, cut a deep X across the top of the loaf about 1/2 inch deep. Bake for 35 to 40 minutes, or until golden brown and a skewer inserted in the center comes out clean.
07 - Transfer the loaf to a wire rack and cool for at least 30 minutes before slicing to allow the crumb to set.