*To make your own buttermilk for this recipe, add 2 1/2 Tbsp. white vinegar to a bowl and stir in 2 1/2 c. whole milk. Let it sit for about 5 minutes so it can go sour. You'll see that the milk has curdled a little.
Warm the buttermilk in the microwave just until it's nice and warm, but not too hot. It should be warm to the touch, but not too hot, or it will kill your yeast. Mine was the right temperature after 1 minute in the microwave. Make sure to stick your finger in it and make sure it's not too hot.
Add the warmed buttermilk to the bowl of an electric mixer and sprinkle the yeast over the top. Sprinkle sugar over the top of the yeast. Stir it a little, then place a plate over the top and wait for about 7-10 minutes for the yeast to get frothy.
Next, add melted butter, salt, and 3 1/2 cups bread flour and mix until the flour is incorporated, using the dough hook attachment.
Gradually add 2 to 3 cups more flour until the dough comes together in a cohesive ball that clears the bottom and sides of the bowl and doesn’t leave a lot of doughy residue on your fingers when touched. It will still be just slightly tacky (you don't want it to be overfloured and dense). Be very careful about adding flour in the end. Add it slowly, mixing in between, just until the dough reaches a nice consistency and isn't overly sticky, but isn't too dense either. The flour amount in the recipe is an estimate and the amount that you add will vary, depending on where you live and the weather and the day.
Knead in the mixer on a medium speed for 6 minutes. Cover bowl and let dough rise in a warm place until the dough has at least doubled in size, about one hour. Mine takes a little over an hour.
Punch dough down and divide it into two equal pieces.
Grease well two 8 1/2-inch by 4 1/2-inch bread pans.
Form each piece of dough into a thick rectangle about 8-inches long; roll it up, pressing on the seams, and pinching the final seam together.
Place the dough loaves into the prepared pans, seam side down. I like to punch the dough into the pan so it spreads out and touches the sides.
Let rise until doubled and the dough has risen about 1-inch above the top rim of the pan, about an hour or so, depending on the temperature of your house.
Bake at 350 degrees Fahrenheit for about 25-30 minutes until golden in color. Remove bread from oven and immediately remove it from the pans to a cooling rack. Rub butter over the tops of the hot loaves, if desired. This will soften the crust. Let cool, then slice.
The bread can be stored at room temperature, in an airtight bag, for a couple days, or frozen for up to a month or so.
