Ingredients

• 2 cups whole-wheat flour
• 2 cups all-purpose flour plus additional for kneading
• 1/2 cup toasted wheat germ
• 2 teaspoons salt
• 2 teaspoons sugar
• 1 teaspoon baking soda
• 1/2 teaspoon cream of tartar
• 1 stick (1/2 cup) cold unsalted butter, cut into 1/2-inch cubes
• 2 cups well-shaken buttermilk

Instructions

1. Put oven rack in middle position and preheat oven to 400°F. Butter a 9- by 2-inch round cake pan.
2. Whisk together flours, wheat germ, salt, sugar, baking soda, and cream of tartar in a large bowl until combined well. Blend in butter with a pastry blender or your fingertips until mixture resembles coarse meal. Make a well in center and add buttermilk, stirring until a dough forms. Gently knead on a floured surface, adding just enough more flour to keep dough from sticking, until smooth, about 3 minutes.
3. Transfer dough to cake pan and flatten to fill pan. With a sharp knife, cut an X (1/2 inch deep) across top of dough (5 inches long). Bake until loaf is lightly browned and sounds hollow when bottom is tapped, 30 to 40 minutes. Cool in pan on a rack 10 minutes, then turn out onto rack and cool, right side up, about 1 hour.