Step 1: Preheat and Prep
Preheat your oven to 350°F (175°C).
Line a 9×13-inch baking pan with parchment paper, leaving some overhang for easy removal.

Step 2: Make the Brownie Batter
In a medium saucepan, melt the butter over low heat. Remove from heat and whisk in the sugar until smooth.
Add eggs one at a time, whisking well after each addition. Stir in vanilla extract.
In a separate bowl, sift together flour, cocoa powder, salt, and baking powder.
Gradually stir dry ingredients into the wet mixture until fully combined.
Pour the batter into the prepared pan and spread evenly.

Step 3: Bake the Brownies
Bake for 25–30 minutes, or until a toothpick inserted comes out with a few moist crumbs.
Let the brownies cool completely in the pan before adding the cookie dough layer.

Step 4: Make the Edible Cookie Dough
While the brownies cool, prepare the cookie dough layer.
In a large bowl, cream the softened butter, brown sugar, and granulated sugar until light and fluffy.
Mix in the milk and vanilla extract.
Gradually add the heat-treated flour and stir until smooth.
Fold in the mini chocolate chips.

Step 5: Assemble the Layers
Once the brownies are completely cool, gently spread the cookie dough over the brownie base.
Use a spatula to press it evenly across the top. Chill in the refrigerator for at least 1 hour to set.

Step 6: Add Optional Toppings
Sprinkle extra mini chocolate chips over the top or drizzle with melted chocolate or ganache.
Let chill again for 15–30 minutes if topping with ganache to set properly.

Step 7: Slice and Serve
Lift the brownie slab from the pan using the parchment paper overhang.
Use a sharp knife to slice into squares or rectangles.
Serve chilled or at room temperature.