Preheat oven to 350 degrees Fahrenheit. Line 2 baking sheets with parchment paper and set aside.
Using a fine mesh sieve, sift the flour, malted milk powder, cocoa powder, baking powder, and salt into a large bowl. Set aside.
In the bowl of a stand mixer, cream the butter and sugar until smooth. With the cold butter, you may need to turn up the speed a little bit, but your mixer can handle it.
Add the eggs one at a time and beat each for a minute.
Add the vanilla. The mixture may look curdled, but it will come together just fine when the dry ingredients are added.
On low speed, mix in about half the dry ingredients until just incorporated.
Beat in the milk until smooth.
Mix in the rest of the dry ingredients until incorporated.
Remove bowl from mixer and stir in the Whoppers and chocolate chips.
Using a #60 cookie scoop, portion out the dough 2 inches apart on the baking sheets.
Bake one sheet at a time for about 11 minutes, or until the cookies are puffed up and set.
Leave on baking sheet for 2 minutes before removing to wire racks to cool completely.