Line a baking pan or cast iron pan with parchment paper or coat it with oil.
Combine whole-wheat flour, all-purpose flour, sugar, baking powder, baking soda, salt, raisins, and caraway seeds in a large bowl.
In a separate bowl, whisk an egg then add the buttermilk and yogurt to the egg; whisk them all together.
Add the wet mixture to the dry mixture and combine with an electric mixer at medium to low-speed.
Mound the dough into two prepared pans and bake for 40 minutes.
Notes
If buttermilk is not available, you can make your own by adding 2 tablespoons of white or apple cider vinegar to the whole milk a few minutes before adding it to the batter.
You can make this recipe with all whole wheat flour or all white flour. The bread will be more dense if all whole wheat flour is used.
This recipe makes two loaves of bread, you can freeze one loaf by wrapping it in parchment paper and then foil or freezer paper after it has baked and cooled off. Store it in the freezer for 3 to 4 months. To thaw, remove the bread from the freezer and let it sit at room temperature.