Preheat oven to 375 degrees
Prepare a sheet pan with non-stick foil or grease
In a large bowl, mix all dry ingredients
Add buttermilk, cubed butter, and egg, and stir until incorporated.
Cover a clean work surface with a dusting of flour and turn out the dough and knead a few times.
Shape the dough into a round.
Use a sharp knife to cut an x on the top of the dough.
Brush with the buttermilk and butter mixture.
Place dough in the oven and cook for 50 minutes or until when tested with a toothpick is done (brushing with the buttermilk and butter mixture every 15 minutes)