Prepare brownie recipe as directed and allow to cool completely. Spread vanilla ice cream over cooled brownies, then sprinkle peanuts evenly over ice cream. Place in freezer until ice cream is completely firm, at least 2 hours.

Topping: Combine powdered sugar, evaporated milk, chocolate chips, and butter in medium saucepan over medium-high heat. Bring to a boil and cook 8 minutes, stirring constantly. Remove from heat and stir in the vanilla. Cool for 30 minutes.

When cooled, pour chocolate topping evenly over ice cream and peanuts. Return to freezer for at least 2 hours, or until firm. Let sit at room temperature 5-10 minutes before slicing and serving.