Line a 9-inch square baking dish with plastic wrap, leaving a 1-inch overhang on all sides.
Heat chocolate and evaporated milk in a saucepan over medium heat, stirring, until chocolate melts and is smooth. Remove from heat. Stir in vanilla. Set aside 1/3 cup.
Combine cookies, 2 cups coconut, 1 cup peanuts, the sugar, and 1/2 teaspoon salt in a bowl. Pour in chocolate mixture; stir until combined.
Spread mixture evenly into dish. Spread reserved 1/3 cup chocolate over top. Finely chop remaining 2 tablespoons coconut and 2 tablespoons peanuts; sprinkle evenly over chocolate. Refrigerate until set, about 2 hours. Remove brownies from pan by lifting plastic wrap. Remove plastic, and cut into 24 brownies.
Storage: Brownies can be refrigerated for up to 1 week.