Preheat oven to 425°F. Butter 9x5x3-inch loaf pan. Combine first 8 ingredients in large bowl; mix well. Add butter; rub in with fingertips until mixture resembles fine meal. Stir in enough buttermilk to form soft dough. Transfer dough to prepared loaf pan. Bake until bread is dark brown and tester inserted into center comes out clean, about 40 minutes. Turn bread out onto rack. Turn right side up and cool on rack.