This is a batter bread rather than a yeast bread, which makes it quick to create. It has great staying power and improves with age. Serve with cream cheese or butter for a moist, tasty snack.
Butter a 9 x 5-inch loaf pan and set aside.
Place the flours, sugar, salt, baking soda and raisins in a medium-size bowl, and whisk to combine.
In another small bowl, whisk together the buttermilk and molasses. Pour the buttermilk mixture into the bowl with the flour and stir to combine.
Transfer the batter to the prepared pan and let the pan sit at room temperature for 1 hour, during which time the batter will rise considerably.
Position a rack in the lower third of the oven, and preheat to 275 degrees F. Transfer the loaf pan to the oven and cook until the bread is set, the edges shrink slightly from the sides of the pan, and a toothpick inserted into the center of the loaf comes out clean, 60 to 75 minutes.
Remove the pan from the oven and cool on a wire rack for 10 minutes. Turn the bread out of the pan and continue cooling on the wire rack. To store, wrap tightly in plastic wrap and leave at room temperature for up to 4 days. The bread can be frozen for up to 3 months.