Prepare the muffin pan by greasing the cups generously with butter or cooking spray and set aside. You can also use paper liners.
In a large bowl, beat butter and both the sugars, using an electric hand mixer at medium-high speed, until it turns light and creamy, about 2-3 minutes.
In another bowl, whisk the flour, salt, and baking powder and set aside. This is your dry mixture.
Now, add the eggs and vanilla into the butter-sugar mixture and beat on medium-high speed until combined well. This is your wet mixture.
Gently fold the dry mixture into the wet mixture in three equal and separate additions, alternating with the milk and ending with the dry mix. Make sure that you only mix until the flour disappears. Do not over mix as that can make your muffins too dense.
Gently fold in ¾ cup of the chocolate chips, using a silicone spatula, until evenly distributed. Do not over mix.
Preheat the oven to 425° F and let the batter rest while the oven is heating.
Divide the batter evenly between the muffin cups, filling almost to the top. Sprinkle the extra chocolate chips on the top.
Bake in a preheated oven at 425° F for 5 minutes, then without opening the oven door, reduce the temperature to 350° F and bake for another 13-15 minutes, or until the muffins turn golden brown on top and a toothpick inserted in the middle comes out clean.
Allow the muffins to cool in the pan for 5 minutes before removing to a wire rack for further cooling, or serve warm.