In a large mixing bowl, whisk together the melted butter and granulated sugar until well combined.
Add the eggs and whisk until smooth.
Add the sour cream and vanilla.
Then whisk until fully incorporated.
In a separate bowl, whisk together the all-purpose flour, Dutch process cocoa powder, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture and mix gently until combined.
Pour in the whole milk and whisk until a smooth chocolate batter forms.
Fold in the mini semi-sweet chocolate chips until evenly distributed throughout the batter.
Divide the batter evenly among the paper-lined muffin cups.
Sprinkle the remaining mini chocolate chips over the tops of the muffins.
Bake until the muffins are risen and set in the center.
Remove the muffins from the oven and let them cool in the pan for a few minutes.
Transfer the muffins to a wire rack and let them cool completely.
Your Double Chocolate Muffins are ready to serve. Enjoy!
