1 1/2 cups buttermilk or plain yogurt, thinned with milk to the consistency of buttermilk
1Preheat oven to 375F.
2In a large bowl, stir together the flours, salt, sugar, baking powder, baking soda and salt. Add the butter and blend (or pulse the mixture in the food processor) until well combined and crumbly. If you like, add grated cheese, herbs, nuts or dried fruit at this point. Make a well in the middle of the flour mixture and add the buttermilk, stirring until blended.
3Knead the dough until it comes together in one piece, then knead the ball 10 times. Place on a baking sheet or in a buttered 8" or 9" round cake pan.
4Bake for 1 hour, or until golden and the bread sounds hollow when tapped. Cool on a wire rack.