In a large bowl add the butter & sugar, mix with an electric mixer until fluffy.
Mix in the sourdough discard, sour cream & vanilla.
Add eggs one at a time & beat after each addition.
Add the dry ingredients & mix until just combined.
Pour for batter into a greased or parchment lined loaf pan.
Bake 350 degrees for 45-60 minutes or until a toothpick inserted comes out clean.
Run a butter knife along the sides & cool for 10 minutes before removing from the pan, slice & serve warm or finish cooling completely on a cooling rack.
