1.  Preheat oven to 350 degrees.  Line muffin pan with liners.  Mix together sugar, butter and oil.  Beat in eggs, one at a time until well incorporated.  Stir in vanilla, buttermilk, zucchini and chocolate chips.

2.  In separate bowl, mix together all the dry ingredients.  Add the liquid and mix until combined being careful not to over-mix.  Scoop batter into muffin liners and sprinkle a few extra chocolate chips on top.  Bake in center of the oven for 12-15 minutes until wooden skewer inserted in the center comes out clean.  Be careful not to over-bake or you will end up with a dry muffin.

3.  Remove from pans and allow to cool.  They are best served after they have been stored overnight in an airtight container.