Preheat oven to 180C/350F and grease a 12 hole muffin tin with butter.
Squeeze out all the moisture from the zucchini. I weigh out 250g and then I squeeze out the moisture. Set aside.
Mix the sourdough starter, eggs, buttermilk and melted butter in a bowl. Whisk together until well combined.
In a separate bowl mix together shredded zucchini, all purpose flour, salt, baking powder, 3 different cheeses and chives. Make sure that the zucchini is completely coated in flour.
Now pour the liquid ingredient mixture into the dry ingredients. Gently fold together until just mixed - don't over mix or the muffins will be tough.
Spoon mixture into greased muffin tin. This recipe will fill a 12 hole muffin (each hole around ¾ full).
Bake at 180C/350F for approximately 20 minutes or until muffins are golden brown.
Allow the muffins to cool on a rack for around 15 minutes before enjoying them. They are delicious warm or cold.