
Preheat oven to 350F (177C) and line a 13x9” metal pan (see note) with parchment paper, or lightly grease and flour the pan. Set aside.
In a large mixing bowl, stir together melted (cooled) butter and sugar until combined.
Add eggs, vanilla extract, and milk and stir well.
In a separate, medium-sized mixing bowl, whisk together flour, baking powder, and salt.
Gradually add dry ingredients to wet, stirring after each addition until completely combined.
Add cookie pieces, chocolate chips, and sprinkles and stir well.
Spread batter evenly into the prepared pan and bake in preheated 350F (177C) oven for 32-35 minutes. When finished baking, the edges will just begin to turn a light golden brown and a toothpick inserted into the center should come out clean or with a few moist crumbs.
Allow to cool in pan before cutting and serving.