Sourdough Buttermilk Biscuits (adapted from bakingsense)

Pre-heat your oven to 190°C.

Combine all dry ingredients together in a large bowl.

Cut the cold butter into pieces (approximately 2 by 2 cm ? but it doesn't have to be precise) and mix it roughly into the dry ingredients until most of it is incorporated but a few pea-sized pieces remain.

Mix the buttermilk and the sourdough starter. Pour into the butter + flour mix. Mix until almost combined.

Flour your work surface well, and turn out the dough. Flour your hands, and very gently knead the dough 3 or 4 times. You want the bare minimum of flour added and the bare minimum of kneading... just get it to where it starts to come together and is just becoming handleable, then gently pat it out to a 1 cm thick pad.

Fold the dough into two. Roll again to a 2 cm thick pad.

Using a biscuit cutter, cut out your biscuits. When you've cut all you can on the first round, regather your dough, press it back out into a pad, and cut a couple more. When you're left with scraps, mush those together into the one or two ugly ones that are the hallmark of a batch of homemade biscuits.

Place your rounds on a baking tray covered with parchment paper. Brush them with some buttermilk and bake them for 15 minutes, or until golden brown.