First prepare fudge brownie as per the instructions on that recipe post but you will be baking the brownies in an 8" x 8" square pan instead
While they are baking prepare the buttercream recipe, this is going to give you slightly more than you need to ice an 8" x 8" square brownie, but just use as much as you like & freeze or refrigerate the rest for later
Add the creme de menthe flavoring to the buttercream at the last stage of mixing along with the optional green food coloring
Make the ganache recipe while the brownies are cooling
Ice the cooled brownies with the creme de menthe buttercream, refrigerate to set the buttercream to cold and then pour the warm (not hot!) ganache over top
Sprinkles are optional
Notes
Storage Creme de Menthe Brownies can be stored at room temperature for up to 1 weekRefrigerate or freeze for longer storage wrapped well to prevent drying