Preheat your oven to 325°F / 165°C. Thoroughly grease an 8x4-inch or 9x5-inch loaf pan.
In a large bowl, whisk together the dry : whole wheat flour, cornmeal, salt, and baking soda.
In a separate medium bowl, stir the molasses into the buttermilk or yogurt until well combined.
Pour the wet into the dry .
Stir with a spatula only until just combined—do not overmix. The batter will be thick.
Scrape the batter into your prepared loaf pan and smooth the top.
Bake for 55-65 minutes, or until a toothpick inserted into the center comes out clean.
Let the loaf cool in the pan on a wire rack for 15 minutes before turning it out to cool completely.
Do not overmix!
Stir the batter only until the flour streaks disappear. Overmixing develops gluten and will result in a tough, dense loaf.