Directions

1. Use a food processor to crush the sandwich cookies (alternately, place them in a gallon-size zip-lock bag, press the air out of the bag and seal it, then use a rolling pin to crush the cookies). This will be your graves' "dirt."
2. Next, use a microwave or double boiler, to heat the chocolate chips, 1/4 cup water and the butter until the chocolate and butter are melted.
3. Use a small whisk or fork to stir until very smooth.
4. Let chocolate mixture cool for about 10 minutes.
5. Pour about 3 tbsp of the chocolate mixture into a small bowl and set aside.
6. Fill a large bowl about half-way full with ice and set aside.
7. In a small heavy saucepan, whisk egg yolks, sugar and remaining water.
8. Cook and stir over low heat until mixture begins to thicken, about 2 minutes.
9. Remove from the heat; whisk in chocolate mixture. Set saucepan in ice and stir until cooled, about 5-10 minutes.
10. Fold in whipped cream until completely combined. Place bowl of chocolate mousse in the refrigerator.
11. Use a rubber scraper to transfer the reserved chocolate into a pastry bag with a very fine tip. If you don't have a pastry bag (I don't), use a plastic sandwich bag. Push the chocolate all the way into a corner and use scissors to snip the tiniest corner off (no more than 1/16th of an inch). Then use your bag of chocolate to pipe the letters "RIP" or anything else you like (it might be fun to pipe your guests' initials) onto the top half of each Milano cookie.
12. Place the finished cookies on a clean plate and place it in the refrigerator to encourage the chocolate to set.
13. To assemble the graves, divide the mousse betwee 6 short glasses.
14. Top with a handful of the chocolate cookie "dirt" and push the end of a Milano tombstone into the "dirt." Add a sprig of fresh mint if you like.
15. Serve immediately or refrigerate for up to 4 hours.