For the Brownie Bottom

• Preheat the oven to 350 and line a 9X13 pan with parchment paper, leaving an overhang so that the mousse cake can be easily lifted out of the pan for serving.
• In a large bowl, whisk together the melted butter and sugars until well combined. 
• Add in the eggs and vanilla and whisk for 2-3 minutes, until smooth and light in color.
• Add the flour, cocoa powder, espresso powder, and salt. Fold together with a rubber spatula until just combined.
• Stir in the chocolate chips.
• Pour the batter into the prepared pan and spread into an even layer with an offset spatula. Bake at 350 for 15 minutes. Allow to cool completely.

For the Chocolate Mousse

• In a large bowl or in a stand mixer with the whisk attachment, whip the cream until stiff peaks form. Place ½ C of the whipped cream in a separate bowl.  Set both bowls of whipped cream aside.
• In a medium sized microwavable bowl, melt the chocolate chips in 30 second increments stirring in between until completely melted and smooth.
• Stir in the sweetened condensed milk. It will get very thick.
• Grab the large bowl of whipped cream, and add 1 C to the sweetened condensed milk mixture. Gently fold it together using a rubber spatula. It will seem hard to get incorporated at first because the SCM mixture is so thick, but just keep folding it will come together.
• Once incorporated, take the entire sweetened condensed milk mixture and add it to the remaining large bowl of whipped cream. Fold together gently until well combined. Spread the chocolate mousse over the cooled brownie bottom into an even layer. Cover and place in the fridge for at least an hour, up to overnight.

For the Whipped Cream Ghosts

• Take the ½ C of whipped cream that was set aside and add it to a piping bag with a small round tip. Pipe the little ghost shapes by applying pressure at the top, then letting go a bit as you pull down then lift for the little ghost tails. Use black sprinkles for the eyes and mouths.