In a large mixing bowl, sift the flour and cocoa powder. Whisk in baking powder, baking soda, salt, sugar, and chocolate chips.
2 cups All-purpose flour, ½ cup Unsweetened cocoa powder, 2 ½ teaspoon Baking soda, ½ teaspoon Baking powder, ½ teaspoon Salt, 1 cup White granulated sugar, 1 ¾ cup Semisweet chocolate chips
In a separate bowl, mix the sour cream, vanilla, buttermilk, eggs, melted chocolate, and oil.
½ cup Oil, ½ cup Sour cream, 1 teaspoon Pure vanilla extract, 2 Large eggs, ¾ cup Buttermilk, 4 oz Semisweet chocolate bar
Pour the wet ingredients into the dry ingredients. Use a rubber spatula to fold the batter until just combined. Be careful not to overmix the batter.
Place plastic wrap over the over (or a kitchen towel) and let it sit for 20 minutes. This will help the muffins rise higher.
Preheat oven to 425°F. Line a 12 cup muffin tin with muffin liners. This makes 16 muffins, if you have a second muffin tin, line it with 4 muffin liners. Set aside.
Use an ice cream scoop and fill the muffin tin all the way to the top.. Top with chocolate chips and a sprinkle of sugar.
Bake for 5 minutes. Reduce the oven temperature to 375° and bake for 12-15 minutes. Bake until a toothpick inserted comes out with moist crumbs or clean.
Let the muffins sit in the hot pan for 10 minutes before transferring to a cooling rack.