Step 1

Preheat the oven to 425°F and line a muffin pan with 6 paper liners. Set aside.

Step 2

In a medium-sized bowl whisk together the all-purpose flour, granulated sugar, baking powder, and salt.

Step 3

In a separate bowl whisk together the buttermilk, sour cream, oil, egg and vanilla extract until combined.

Step 4

Fold the dry ingredients into the wet ingredients with a rubber spatula, and mix until just until combined (DO NOT OVERMIX YOUR BATTER!). Your batter should not be all the way smooth, and it's ok if there are still some small chunks in it.

Step 5

Gently mix the flour-tossed bits of chocolate into the batter until they're evenly distributed.

Step 6

Divide the muffin batter evenly between the 6 muffin cups, filling them to the top of the liner.

Step 7

If desired, add a sprinkle of coarse sugar and a few extra pieces of chocolate on the top of each muffin.

Step 8

Bake the muffins for 6 minutes at 425 degree F to give the muffins a nice rise and a domed, golden brown top, then (keeping the muffins in the oven) reduce the oven temperature to 350°F. Continue to bake for an additional 22-25 minutes.

Step 9

Let the muffins sit in the pan for 10 minutes to cool, then move them to a wire rack to finish cooling.