In the bowl of a stand mixer, or with a hand mixer, cream together the butter and sugar until light and fluffy (about 3-5 minutes on high). Add the egg and vanilla one at a time, mixing until combined between each addition. In a separate bowl, whisk together the flour, baking soda, salt, and malted milk powder. Add these dry ingredients to your mixer, half at a time, mixing until combined. It will appear dry, we’ll fix that before we put the dough aside to chill.