Preheat oven to 425 degrees F. Line a muffin pan with muffin liners or spray with nonstick spray.
In a large bowl, mix together flour, baking powder, salt and chocolate chips. In another bowl, combine the butter, granulated sugar, buttermilk, oil, sour cream, eggs and vanilla. Pour into the dry mixture and fold until the batter just comes together.
Fill muffin cups just about to the top of the liners. Sprinkle with coarse turbinado sugar. Bake for 8 to 10 minutes.