In the bowl of a stand mixer, affixed with the paddle attachment, add the butter, brown sugar and white sugar. Mix on medium-high speed until light and fluffy. Add in the eggs and vanilla extract and mix until fully incorporated.

Change the mixer to low speed and add the cocoa powder, malted milk powder, flour, baking soda, salt and cornstarch. Mix until just incorporated. Remove the bowl form the mixer and use a rubber scraper to fold in the chocolate chips.

Chill dough in the refrigerator for 1-hour or in a covered container overnight (I find it easiest to scoop to cookie dough into cookie dough balls before chilling the dough).

Once dough has chilled, preheat oven to 350-degrees and line cookie sheets with parchment paper. Use a medium sized cookie scoop to scoop cookie dough onto the prepared cookie sheets.

Bake cookies, one cookie sheet at a time, in 350-degree oven for 10-minutes. Do not over bake. Bake only until the center of the cookies are not raw looking. Allow cookies to set on the cookie sheet for 5-minutes before transferring to a cooling rack to cool completely.