Preheat the oven to 350.
In a large, microwave-safe bowl, add the butter and chocolate. Microwave for 1 minute, then stir until the chocolate is fully melted and the two have created a smooth mixture. Add in the eggs, sugar, salt and vanilla and mix in.
Add the flour and stir for 50 strokes until the mixture is evenly and thoroughly combined.
Spray a 9x9 square baking pan with nonstick spray, or line with parchment paper.
Pour in approximately ⅓ of the batter and spread to all four corners. Create one layer of cookies on top of the batter. Repeat with another ⅓ of the batter and another layer of cookies.
Pour the remaining batter on top and evenly spread around the pan, making sure the cookies are all covered.
Place the remaining cookies in a small sandwich bag and crush with a rolling pin. Sprinkle on top of the brownie batter.
Bake for 35 minutes, or until a toothpick inserted comes out clean. Allow to cool to warm before cutting and serving.