01 - Preheat the oven to 375°F. Line two baking sheets with parchment paper or silicone mats.
02 - Whisk together all-purpose flour, cocoa powder, baking powder, baking soda, and salt in a medium bowl.
03 - In a large bowl, whisk melted butter with granulated and brown sugars until smooth. Add eggs one at a time, beating well after each addition, then stir in vanilla extract.
04 - Add half of the dry ingredients to the wet mixture and mix gently. Pour in buttermilk, then add the remaining dry ingredients. Stir until just combined, avoiding overmixing.
05 - Fold semisweet chocolate chips into the batter.
06 - Using a large cookie scoop or 1/4 cup measure, drop mounds of batter onto the prepared baking sheets, spacing them approximately 2 inches apart.
07 - Bake for 10 to 12 minutes until edges are set and centers appear just baked. Avoid overbaking.
08 - Let muffin tops cool on the baking sheets for 5 minutes, then transfer them to a wire rack to cool completely.