The day before, remove your starter from the fridge.

Take at least 1 cup of it, leaving only a small amount to culture a new batch.

Add 1¬Ω cups of the flour mixture and enough of the buttermilk to blend to a stiff batter.

Cover and allow the sourdough to feed overnight.

It should be bubbly by the next day.

Give your remaining starter a good feeding and leave it out overnight until it starts showing signs of life before returning it to the fridge.

Generously grease a 9x5-inch loaf pan.

Set aside.

In the bowl of a stand mixer fitted with the paddle attachment, mix the remaining flour, xanthan gum, cream of tartar, sugar, salt and yeast to combine.

Add Sourdough Starter and butter and mix to combine.

With the mixer on low, pour in the milk and Scotch in a slow, steady stream.

Once the flour has begun to incorporate the liquids, beat the ingredients on at least medium speed for 4 to 6 minutes.

The dough will be pretty sticky—thicker than cake batter, not quite as thick as cookie dough.

Scrape the dough into the greased loaf pan and smooth the top with wet hands.

Allow the dough to rise in a warm, humid place for 30 to 45 minutes or until it has about doubled in size.

While the dough is rising, preheat the oven to 160ºc.

Bake the loaf in preheated oven for 40 to 45 minutes.