In a large bowl, add flour to the butter.

Cut butter into flour using a fork, food processor, pastry cutter, or with your hands, The butter should kind of disappear into the flour.

Add 1 cup of sourdough starter to the flour mixture.

Add sugar and stir until nicely incorporated.

Add the buttermilk and stir again until all the ingredients are well incorporated.

Place a clean tea towel over the bowl and allow it to sit at room temperature for at least 8 and up to 24 hours. The longer it sits, the more fermented and sour it will be.

The next day, preheat the oven to 400 F. Add the baking soda and the salt to the fermented dough by evenly sprinkling them over the fermented dough to avoid chunks. The baking soda is the rising agent for this recipe.

Mix to incorporate the baking soda and salt very well using a wooden spoon, mixer with the paddle attachment, or your hands.

Tip the dough into a 12 or 16" cast iron skillet or a Dutch oven. Pat the dough into a round as best you can. This is a shaggy dough, so don't worry about it looking perfect. Score the dough by cutting a cross shape on the top of the loaf.

Bake in a 400 degrees F oven until golden brown and a skewer inserted into the center of the loaf comes out clean or the internal temperature reaches 180 degrees, 30-40 minutes. Remove the loaf from the oven and brush the top of the bread with melted butter. Cool to the loaf of breadroom temperature before slicing. Use a serrated sharp knife to cut the bread, it can be a little crumbly.

Serve with Irish butter or jam as a delicious breakfast or side dish.