Preheat the oven to 350ºF. Line two baking sheets with parchment paper.

In a medium bowl, sift together the flour, malted milk powder, cocoa powder and salt.

In the bowl of a stand mixer, beat the butter and the sugar together until light and fluffy, 3 minutes. Add in the eggs, one at a time, beating for 1 full minute after each addition. Scrape down the sides of the bowl as needed. Beat in the vanilla. (The mixture may look curdled - don’t be alarmed.) Reduce the speed of the mixer to low, and add in half of the dry ingredients. Mix just until combined. Add in the milk and the remaining dry ingredients, mixing just until incorporated. The batter will be thin, resembling a frosting more than cookie dough. Using a spatula, fold in the malted milk balls and chopped chocolate.

Using a cookie scoop or a spoon, drop the dough onto the prepared baking sheets, using about 1 tablespoon of dough per cookie, leaving at least 2 inches between each.

Bake for 11 to 13 minutes, rotating the sheets halfway through the baking time. When the cookies are done, they will be puffed and set, and they will still be slightly soft to the touch. Let the cookies cool for 2 minutes before transferring the cookies to a cooling rack to cool completely.