Pre-heat the oven to 350f/180c
Cream the butter and sugar really well in a bowl or stand mixer, until lights, fluffy and pale in colour
Add in the eggs, and whisk to combine, then add in the milk, sourdough discard, and vanilla
Meanwhile, combine the dry ingredients in a separate bowl.
Switching to a spatula or dough whisk, add the dry ingredients a little at a time and mix carefully, just combining the ingredients. It's important not to over mix at this point if you want a light fluffy cake.
Pour the batter into the prepared cake tin/loaf pan and bake for 45-50 mins, until a skewer comes out clean.
Allow to cool slightly before serving
