Line an 8X8 pan with parchment paper

In a 2-quart sacepan, melt the butter over medium- low heat. Bring the heat up to a simmer and stir with a non-stick spatula. Butter will begin to making popping sounds, do not let it brown! We just want to cook out some of the water. Cook until the hissing and popping noises stop

Remove from heat and strain the butter into a bowl. Let cool for 5 minutes until room temperature

Add in the vanilla, salt and powdered sugar. Mix thoroughly, with a wooden spoon or hand mixer until it is creamy and soft

Spread this filling onto the parchment lined pan and freeze

Freeze at LEAST 4 hours and preferably overnight- the harder this is, the more likely it will not melt in between the layers

In a medium bowl, with a handmixer, cream the butter and sugars on high for 3-4 minutes or until light and fluffy, scraping the bowl with a nonstick spatula down as needed

Add in the malted milk powder, vanilla and egg. Mix again and scrape the bowl down once more

In a small bowl combine all dry ingredients - baking soda, powder, flour, and salt

Pour in the dry mix into the sugar mixture and mix until combined

Add in chocolate chunks/chips, reserving a handful to sprinkle on top later

Place in the refrigerator, covered with cling wrap until ready to use

Preheat the oven to 350F

Line an 8X8 square pan with parchment paper, making sure to leave overhang so you can lift the brownies out when they are done (if you only have one pan and it is being used for the frozen filling, feel free to now put that filling in a bag while you make the rest of the recipe)

Measure out the chocolate chips and place them in a heat-proof bowl or measuring cup, set aside. In a medium saucepan, add the butter and turn the heat to medium, turn the heat to medium-high, and let the butter foam and sputter until it starts to turn a golden brown. Swirl the pan around making sure to remove the pan from the heat as you see the butter darken to a deeper brown. Pour the browned butter directly over the chocolate chips and let sit for at least 3 minutes. The heat of the butter will melt the chips!

Then stir using a spoon or nonstick spatula until the chips and the butter are completely smooth. In a separate large bowl add the granulated sugar, light brown sugar, eggs, vanilla extract, and both cocoa powders.

Whisk vigorously until the mixture is completely smooth and lightens in color. Add in the browned butter and chocolate mixture and mix until smooth. Add in the flour and salt and mix again until smooth. Pour all of the batter in the pan and smooth it out with an offset spatula, then place the frozen oreo cream on top.

Scoop the cookie dough on top of the oreo filling and spread into an even layer

Bake until completely cooked through - 40-50 minutes (if cookies look like they are getting too brown on top, place foil over the top of the bars ½ way through cooking)

Remove from oven and let cool COMPLETELY

Slice and enjoy!