For the Soaker: In a small bowl, combine 3 1/2 cups whole wheat flour, 1 teaspoon sea salt, and 1 1/2 cups of milk plus 2 tablespoons of vinegar (I use raw apple cider).
For the Sponge: In your stand mixer, combine another 3 1/2 cups whole wheat flour, 1/4 teaspoon yeast, and 1 1/2 cups of filtered water plus 2 tablespoons of vinegar. Mix for five minutes. Let rest for five minutes, allowing the wheat to hydrate. Mix for 1 more minute.
Cover both of the bowls with a plate or plastic wrap and set aside until the next day.
Combine all of the soaker and all of the sponge in your stand mixer. Add in 1 teaspoon sea salt, 2 tablespoons of softened butter, 5 tablespoons of rapadura (or sweetener of choice…though I’ve read honey will make it denser), and 2 1/4 teaspoons of yeast. Knead for 6-8 minutes in your mixer, or 10-15 minutes by hand.
At this point, you may need to add a bit more flour to get the bread to the right consistency. I added about 1/2 cup of extra flour. You want the dough to be pulling cleanly off the sides of the mixer but still be sticking to the bottom of the bowl.
When the dough is kneaded and to the right consistency, transfer it to a buttered bowl, cover, and let rise for about 1 1/2 hours, or until you poke it with your finger and the hole doesn’t fill it.
Divide the dough into two equal pieces. On a floured surface, gently shape the dough into a loaf, tucking the sides and ends under.
Place each loaf in a buttered bread pan and allow to rise for another 45 minutes-1 hour, depending on the warmth of your home.
When the loaves have risen to your liking, place in a preheated 350 degree oven for 35-45 minutes, or until they are a dark golden and sound very hollow when tapped with your finger.
When the bread is finished, remove it from the oven and transfer to a wire rack until cool.