Preheat oven to 400°F.

In a large mixing bowl add the flour, baking soda, sugar and salt and mix well with a whisk.

Add the cold cubed butter and cut into the flour mixture using a pastry blender (or use your fingers and rub into pea size balls).

Add the raisins (optional) and stir into the flour mixture. Set aside.

In another bowl add the buttermilk, egg and vinegar and milk well.

Pour into the flour mixture, folding in with a spoon. Keep folding and working the buttermilk into the flour mixture until combined.

Sprinkle counter (or chopping board) with flour, liberally, and empty the dough onto the flour. Dust hands with flour and work the dough, for about 1 minute, until it’s no longer sticky - adding flour as needed to get the right texture (not sticky).

Place dough into a 10” cast iron skillet that is sprayed with cooking spray.

Cut a cross into the top of the dough.

Bake in the oven, uncovered, for 40-50 minutes. To be sure, check with a thermometer - it should be 190-195°F. Cover with foil toward the end if you find it’s browning too much.

Remove from the oven and allow to cool slightly in the skillet, for about 15 minutes before transferring to a wire rack to cool completely.