In 1 bowl add the dry ingredients: flour, sugar, baking powder, baking soda, salt, and chocolate chips. Mix together.
In a 2nd bowl or add to the first bowl, whisk together the wet ingredients: oil, melted butter, buttermilk, vanilla, sour cream, and eggs.
Add the wet ingredients to the dry ingredients and mix together. Don't overmix.
Line muffin pan with liners and fill about ¾ full.
Optional: Sprinkle tops with sugar.
Bake at 450°F for 6 minutes, then lower the temperature to 350°F and bake for 18 minutes. Cooking times will vary.
