1 3/4 cups all purpose flour
1 cup malted milk powder
1/4 cup unsweetened cocoa powder
1 1/2 teaspoons baking powder
1/4 teaspoon salt
1 stick plus 3 tablespoons unsalted butter at room temp.
2/3 cup sugar
2 large eggs
1 teaspoon pure vanilla extract
1/4 cup whole milk (I used 2%)
2 cups (6 ounces) chocolate-covered malted milk balls, coarsely chopped
6 ounces bittersweet chocolate, coarsely chopped or 1 cup chocolate chips or chunks
GETTING READY: Position the racks to divide the oven into thirds and line two baking sheets with parchment or silicone mats.
Sift together the flour, malted milk powder, cocoa, baking powder, and salt.
Working with a stand mixer, preferably fitted with a paddle attachment, or with a hand mixer in a large bowl, beat the butter and sugar together on medium speed for about 3 minutes, until very smooth. Add the eggs one at a time, beating for about a minute after each addition. Beat in the vanilla; don't be concerned in the mixture looks curdled - it will even out when the dry ingredients are added. Reduce the mixer speed to low and add half the dry ingredients, mixing just until they disappear in the batter. Mix in the milk, then the remaining dry ingredients, mixing only until they are incorporated. The batter will look more like fudge frosting than cookie dough - and that's fine. With the mixer on low, or by hand with a rubber spatula, mix in the malted milk balls and chopped chocolate.
Drop the dough by rounded tablespoonfuls on to the sheets, leaving about 2 inches of space between spoonfuls. Bake for 11 to 13 minutes, rotating the sheets from top to bottom and front to back after 6 minutes. When done, the cookies will be puffed and set slightly but soft to the touch. Let the cookies rest for 2 minutes before using a wide metal spatula to transfer them to the racks to cool to room temperature.
Repeat with the remaining dough, cooling the baking sheets between batches.