Line an 8'' baking pan with parchment paper, leaving a little bit of overhang on the sides so that you'll be able to easily pull the brownies out of the pan.
Pour brownie batter into the prepared pan and smooth it into an even layer. Bake according to recipe instructions.
Allow brownies to cool completely. Pull up on the parchment paper and transfer the brownies to a flat surface.
Cut the brownies into rectangles. (I cut mine 4 x 3 to make 12 rectangle brownies).
Mix all of the frosting ingredients together in a bowl. Mix for 2 minutes until light and fluffy. (Add a little more powdered sugar to make the mixture thicker, or another dash of milk to make it thinner, as needed.)
Mix in a few drops of green food coloring. Set aside.
Use the black (edible) gel pen to write the letter R-I-P on the top of each milano cookie. I also cut the very bottom edge off of my cookies to make the "headstones" a little shorter, but you don't have to.
Press each cookie into the top of the brownie, as if it were a grave headstone.
Spoon a a little green frosting onto the bottoms of the candy pumpkins and add them near the cookie.