Preheat oven to 325 degrees.
In the bowl of a standing mixer, add the butter and sugars and beat on medium speed for about 5 minutes, until creamy.
Add the egg, egg yolk and vanilla bean paste, increase speed to high and beat for 2 -3 minutes until light and creamy.
In a small bowl, whisk together the baking soda, baking powder and water.
Reduce mixer speed to low and add the baking soda mixture, flour, malted milk powder and salt. Beat until just combined.
Remove the bowl from the standing mixer and fold in the dark chocolate discs.
Using an ice cream scoop, place cookie dough balls about two inches apart on a parchment lined baking sheet.
Bake for 16 minutes. Remove from oven and cool on wire racks.