Preheat the oven to 350°F. Line 2 baking sheets with parchment paper or lightly grease them.
In a large mixing bowl or the bowl of a stand mixer, combine butter, sugars, cocoa powder, salt, baking powder, baking soda and vanilla extract. Mix until combined.
If you going to add chocolate chips or nuts or any additions - add the milk, if not - skip the milk.
Add the egg replacer, milk and mix until well combined. Scrape the sides and mix again.
Stir in the all purpose flour and espresso powder. Mix well.
Finally stir in the add-ins - chocolate chips or nuts.
Using a tablespoon or a tablespoon scoop, drop 1 tablespoon of the dough on the prepared baking sheet about 2" apart.
Bake for 12~14 minutes or the cookies are not shiny and look set. Remove from the oven and cool on the pan.