Melt the Chocolate Chips to a smooth consistency using Double Boiler or Microwave
Double boiler method: Fill a tall pot about ¼ full with water and bring to a boil. Reduce the heat to a simmer. Reserve 2 tablespoon for later and add ½ cup chocolate chips to a smaller heat-safe bowl and fit in on TOP of the pot such that, there is at least 3″ space between the bowl and water. We used a 3qt Instant Pot for the base and used a glass bowl for melting the chips.
Microwave method: Using 20 seconds increments, melt the chocolate chips in the microwave using the default heat setting. It takes about 40-60 seconds. Time may vary a bit depending on your microwave. Stir every 20 seconds.
Beat Heavy Cream
While the chocolate cools, beat heavy whipping cream and confectioner's sugar, until it makes soft peaks. The time for this depends on quantity, kind of mixing gadget (stand mixer or electric mixer) and speed of mixing. The end result should resemble the consistency of a canned whipped cream.
Make the Mousse
Gently fold in 1 scoop of whipped cream in the melted chocolate chips. Repeat this step, one scoop at a time, till all the whipped cream is nicely folded into the mousse, giving it a milk chocolate color evenly.
For easy assembling, using a spatula transfer the mousse in a piping bag or a gallon size ziplock bag. Seal the bag and push all the mousse to one corner, making a cone shape. Cut ½ inch at the tip and pipe the mousse in small shooter glasses or serving cups, leaving enough room for decoration.
Refrigerate till you assemble on the topping and decoration. If you are making it ahead of time, take the mousse cups out of the refrigerator 10-15 minutes in advance, so that it can soften slightly.
Topping & Graveyard Decoration
Melt remaining chocolate, cool for 5 minutes and transfer the chocolate in a sandwich size ziplock bag, or a small piping bag. You will use this to pipe the letters on the ‘gravestone'(Milano cookie), so make sure that the hole is very small, or it will get messy.
Now comes the fun part! Take a Milano cookie and slowly pipe the words “RIP” on the top half. Set aside for setting. You can also pop them in the refrigerator. These are your gravestones.
Pulse the Oreos in a small food processor, or crush them in a large ziplock bag with the back of a skillet, until it reaches desired “dirt-like” consistency.
Top the mousse with the oreo dirt. Insert one gravestone Milano cookie per glass, at an angle, about ½ way in. Make sure that a good portion of the cookie is still sticking out, and that the ‘RIP’ is very visible. Top with green sprinkles as grass, if desired. Your graveyard Chocolate Mousse is ready! Enjoy!
Notes
If making this dessert as individual portions, assemble them in shot glasses or small dessert cups. It not only looks great, but also works out to be very convenient since you don’t need any plates to serve it in.
If you are feeding a large crowd, you can just make a big batch of this mousse and assemble it in a large shallow glass tray for people to help themselves.
For a smaller quantity, I have found the electric hand-mixer to be more effective then a stand-alone mixer.
This dessert can be made a day ahead of your halloween party. Prepare and pipe the mousse in shot glasses or cups, and chill overnight in the refrigerator. Assemble the dirt and tombstone an hour before the party and stick them back in the refrigerator. Take the mousse cups out of the refrigerator 10-15 minutes before serving.
When piping the letters, RIP, on the tombstone, make sure that the piping hole is very small, or it will get messy.
Note: The nutrition facts below are my estimates. If you are following any diet plan, I recommend cross-checking with your preferred nutrition calculator.