Combine butter, brown sugar, and granulated sugar together. Mix until soft and creamy, about 3-4 minutes.
1 cup butter, ¾ cup brown sugar, ¾ cup granulated sugar
Add vanilla and eggs. Mix well.
2 eggs, 1 teaspoon vanilla
Stir in flour, malted milk powder, baking soda, and salt.
2¼ cups flour, ¼ cup malted milk powder, 1 teaspoon baking soda, ¼ teaspoon salt
Fold in chocolate chips and malted milk balls.
Scoop cookie dough onto an ungreased baking sheet.
Bake in a preheated 375°F oven for 8-10 minutes
Cool on a baking sheet for 1-2 minutes, then remove cookies and place on a cooling rack.
Notes
Cream the butter and sugar together for longer than you might think. Creaming helps add air to the mixture and helps dissolve the sugar crystals. Use a stand mixer for 3-4 minutes (or longer!)
You want softened butter, but not melted.
Use a cookie scoop to get evenly sized-cookies. I used a #40 scoop.