1. Preheat oven to 350 degrees. Mix milk and vinegar; let stand until thickened, about 5 minutes.

2. Whisk together flour, salt, baking powder, and baking soda. Cut in butter with a pastry cutter until mixture resembles coarse meal. Stir in bran, seeds, and raisins.

3. Add milk mixture; stir until dough just holds together but is still sticky. Turn onto a lightly floured surface. Pat dough into a round loaf, about 7 inches in diameter. Transfer to a parchment-lined baking sheet.

4. Lightly dust top of loaf with flour. Using a sharp knife, score an X in top. Bake, rotating halfway through, until loaf is golden brown and a tester inserted in center comes out clean, about 70 minutes. Let cool completely on a wire rack.