Cream together the melted butter (1/2 cup), granulated sugar (1 1/2 cups), and eggs (3) for a few minutes until smooth.
Whisk in the cocoa powder (3/4 cup), flour (1 cup), baking powder (1/2 teaspoon), and baking soda (1/2 teaspoon). Use a spoon or cookie scoop to drop balls of cookie dough onto a large baking sheet. Bake your cookies for 11 minutes. Let them cool for a few minutes before transferring them to a wire cooling rack.
Make Cookie Dough Filling
Line a rimmed cookie sheet with parchment paper. Spread flour (1 1/2 cups) out in an even layer over the parchment. Bake for 7 minutes, or until the temperature of the flour reaches at least 160ºF (71ºC) when measured by an instant-read thermometer. Allow flour to cool completely before proceeding with the filling recipe.
Make your edible cookie dough by creaming together the softened butter (1/2 cup), sugars (1/2 cup white + 1/2 cup brown), and vanilla (1 teaspoon) until smooth.
Whisk in the flour until no dry pockets remain in the cookie dough. Gently fold in the chocolate chips (2 cups).
Place a large scoop of edible cookie dough on half of your brownie cookies. Top with the remaining cookies and push together gently to create 9 cookie sandwiches. Serve and enjoy!
Notes
Heat-treat your flour: This step keeps the filling safe to eat. Don’t skip it!
Bake cookies just until set: Slightly underbaked gives you that chewy brownie texture.
Let everything cool: Warm cookies will melt your filling — patience pays off.
Use a scoop: A cookie scoop keeps everything uniform (and prettier for serving).