Easy in the kitchen, impressive on the table and palate. Topped with a dark chocolate spider, friends and family will delight over their very own chocolate mousse tart.
Preheat oven to 350˚F. Chill a medium-sized (preferably glass) bowl and the beaters from your electric mixer in the freezer.
Pulse chocolate wafers in a food processor until fine.
Combine cookie crumbs, brown sugar, flour, cinnamon, and salt in a medium bowl. Mix well, then add the melted butter. Stir well with a fork, then with your hands. Coat the crumbs until the butter is even in distribution.
Add about 3-4 Tablespoons of crumbs to each removable tart pan. With your hands or a tart tamper, press the cookie crumb mixture into the bottom and up the sides of each pan. Refrigerate on a rimmed baking sheet for 10 minutes.
On the center oven rack, bake the tarts for 6 minutes. Let cool on a wire rack until cooled.
Chocolate Mousse Filling
In a small saucepan over medium, heat a ½ cup heavy cream. When small bubbles form along the edges, remove from heat. Stir the chocolate into the cream until smooth, then transfer to a large bowl and cool to room temperature while stirring occasionally. Cover and place in the refrigerator until chilled, about another hour. Continue stirring occasionally.
Remove the bowl and beaters from the freezer. Using an electric stand or handheld mixer, start on low and beat the remaining 1¼ cups cream with increasing speed until the cream starts to thicken. Increase to high and continue beating until stiff peaks form. Avoid over beating.
Fold the cream into the chocolate. For me — folding with a spatula, then mixing on low speed for about a minute, then folding the remaining streaks seems to work best to incorporate the cream into the chocolate.
If serving immediately:Scoop or pipe the mousse into the tart pans, then garnish with crushed cookies, chocolate shavings, sparkly glitter, sprinkles, whipped cream, or dark chocolate spiders and webs. Once designs are made, place in the refrigerator or freezer until ready for use.If serving later, remove the mousse from the refrigerator and let stand until just soft enough to give one more whip.
Notes
High Altitude
the only change at 6,300 altitude, is using 5 tablespoons of butter in the tart crust vs. 4 at sea level.
Crust
the tart crust can be made ahead, cooled, and covered.
Chocolate
a good quality chocolate makes a difference in this mousse
I prefer 60% or lower
a higher fat heavy whipped cream makes stiffer peaks of mousse too.