Preheat the oven to 400 degrees. Line a muffin tin with 12 cupcake liners or spray with baking spray.

In a large bowl cream together the butter and sugar. Add the eggs and mix well.

Stir in the sourdough discard and the milk and mix until smooth.

In a medium bowl combine the flour, baking powder, and salt. Add to the bowl with the wet ingredients and mix until a thick batter forms.

Add the zucchini and chocolate chips to the bowl and mix until the batter is well combined.

Pour into the prepared muffin tin. Sprinkle with additional chocolate chips.

Bake the muffins for 18-20 minutes or until a toothpick inserted into the center and it comes out clean.

Remove from oven and cool completely on a wire rack before removing from pan.