From Wikipedia: Boxes of the two most popular Girl Scout cookies: Samoas (left) and Thin Mints (right)
Sprinkle Samoa cookie crumbs over brownie batter 1/2 way through the baking time, and gently press in, continue baking remainder of time
You can use your favorite brownie recipe or a store bought mix or this great recipe adapted from "Baked-New Frontiers in Baking"
1 1/4 cups flour
1 tsp salt
2 Tbsps dark unsweetened cocoa powder
11 oz bittersweet chocolate chips
8 oz unsalted butter
1 tsp instant espresso gransules
1 1/2 cups granulated sugar
1/2 cup packed light brown sugar
5 large eggs, at room temp
2 tsps pure vanilla extract
1 box of Samoa cookies, crumbled in a food processor, until desired size
Preheat oven to 350 degrees. Line a 9 x 13 " pan with parchment paper and spray with baking spray. In a med bowl whisk together the flour, salt and cocoa powder. Put the chocolate, butter and espresso in a large heat safe metal bowl set over a saucepan of simmering water. Stir occasionally, until the chocolate and butter are completely melted and smooth. Turn the heat off, but keep bowl over water and add the sugars. Whisk until completely combined, then remove the bowl from the pan. The mixture should be just about at room temp. Add 3 eggs to the mixture and whisk until combined. Add the remaining eggs and whisk until combined. Add the vanilla and stir. Sprinkle the flour mixture over the chocolate mixture, using a rubber spatula, fold the flour mixture into the chocolate mixture until no flour is visible. Pout the batter into prepared pan and smooth the top. Bake in center of oven for 15 mins, then remove from the oven and sprinkle crumbled Samoa cookies evenly over top, gently press in. Rotate pan and return to oven and continue baking 15 more minutes. Remove from oven and let completely cool on rack, then lift out of pan and cut into squares.