1-Preheat oven to 425℉/220℃: Preheat oven to 425℉/220℃. Line the muffin pans with cupcake liners.
2-In a medium bowl, mix all-purpose flour,: In a medium bowl, mix all-purpose flour, cocoa powder, baking powder, baking soda, and salt until well combined. Set aside.
3-In a large bowl, whisk together vegetable: In a large bowl, whisk together vegetable oil, granulated sugar, eggs, milk, vanilla extract, and sour cream until well combined.
4-Sift in the dry ingredients into the: Sift in the dry ingredients into the wet ingredients and stir until well incorporated. Fold in 1 1/2 cups (255 gr) of chocolate chips into the batter.
5-Spoon the batter evenly into each cup: Spoon the batter evenly into each cup or liner, filling each all the way to the top. Distribute the remaining chocolate chips evenly over the muffin tops, pressing them gently into the batter.
6-Bake the muffins for 5 minutes at: Bake the muffins for 5 minutes at 425℉/220℃. Then, keeping the muffins in the oven, reduce the oven temperature to 350℉/180℃. Bake for an additional 15-17 minutes or until a toothpick inserted in the center comes out clean.
7-Allow the muffins to cool for 5: Allow the muffins to cool for 5 minutes in the muffin pans, then transfer to a wire rack to continue cooling.