In the bowl of a stand mixer, combine all dry ingredients until evenly blended.
Pour in buttermilk and molasses. Mix on low until a thick, smooth batter forms.
Scrape the bowl and mix on medium for 2 minutes.
Set batter aside for 30 minutes until slightly thickened.
Preheat the oven to 325° F. Adjust the oven racks so the bread bakes on the lowest rack. Grease or spray an 8" x 4.5" loaf pan with cooking spray.
Spread the batter evenly into the prepared pan and smooth the top.
Place the pan in a larger dish and add warm water to the dish. Add about 6 cups of water to the baking pan.
Cover the whole pan with another sheet of foil.
Bake on the lowest rack for 90-100 minutes. Internal temp should reach ~195°F.
Before removing from the pan, let it rest 10 minutes, then cool completely before slicing.
Notes
Skipping rest time results in a weak structure.
No steam environment creates a dry, dense loaf.
Too much liquid results in an under-set interior.
Cutting while hot makes the bread fall apart.
Doneness Cues
The internal temperature should be ~195°F (90°C).
It should have a firm top and no wet center.
Insert a toothpick into the bread; it should come out clean when the bread is fully baked.
The bread should pull slightly from the edges.
If it’s underbaked, the center will be gummy.
Use caution when removing the foil, as the steam will be very hot and come out quickly. Remove the loaf pan from the steamer and let it cool on a wire rack for 10 minutes.
Storage
Room Temp: 2–3 days (wrapped well)
Fridge: Up to 5 days (can dry slightly)
Freezer: Up to 2 months (slice before freezing)
Reheat:
Toast slices or warm them in the oven to restore moisture.