Preheat oven to 425 degrees
In a large bowl, combine butter and sugar - whisk until fully combined
Whisk in the eggs to the butter and sugar
Add vanilla and sourdough starter to the eggs, butter and sugar - whisk until smooth
Add the buttermilk to the wet ingredients and whisk until smooth
In a medium bowl, combine dry ingredients: flour, salt, baking soda and baking powder
Add the dry ingredients into the wet ingredients slowly. Mix until fully combined.
Fold in two cups of chocolate chips. I like to use 1 cup semi sweet and 1 cup dark chocolate chips.
Add the mixture into cupcake pans - this recipe makes 24 muffins
Bake at 425 degrees for 5 minutes, then reduce heat to 375 and bake an additional 10-12 minutes.