Preheat oven to 350ºF. Spray a 8” x 8” pan with cooking spray or live with foil.
Melt butter in microwave and set aside.
In a bowl whisk together flour, cocoa, malted milk powder, salt and both sugars.
In a large bowl beat 2 eggs, vanilla and melted butter with a mixer until well combined.
Add dry ingredients and combine on low until smooth. Scoop out 1 cup of the batter and set aside.
Pour the batter into the prepared pan and spread out evenly. Top with 3 cups of STUFF (I used 1 /2 cup caramel chips, ½ cup white/dark chocolate swirl chips and 2 cups chopped OMG’s).
Top with remaining batter. Note: the batter is thick so it is difficult to spread over the STUFF, Spoon it out in several blobs and then spread as best you can. It’s worth it!
Bake for 25-30 minutes until centre is just set. Allow to cool fully before cutting into squares. Can be served plain or with a dusting of powdered sugar.