Stir yeast, a pinch of the sugar and water together and set aside while preparing other ingredients. Sift flour, remaining, sugar, baking soda, baking powder and salt into a large bowl.
Cut the butter into the flour until it’s a rough crumbly texture. Stir the yeast mixture into the buttermilk and add it all to the flour. Mix until a sticky dough comes together, wrap and chill overnight.
The next day, preheat oven to 220°C. On a generously floured surface (dough will be sticky), roll out dough to 1/2-inch (1 cm) thick and fold dough over in half, pressing down gently.
Using a 2-inch (5 cm) round cutter, cut out biscuits and place on a parchment-lined baking sheet. Bake 10 to 12 minutes, until just lightly browned.
Serve biscuits warm or freeze and re-warm to serve later.