S'mores Chocolate Mousse

Instructions

1. Whisk the egg yolks, granulated sugar, and salt together in a heat-proof bowl. (I use a small glass bowl or liquid measuring cup.) Set aside.
2. Bring 3/4 cup (180ml) heavy cream to a simmer in a medium saucepan over medium heat. (The remaining heavy cream is used in step 6.) Once simmering, lower the stove’s heat to low.
3. Whisking the egg yolk mixture constantly, pour in 1/4 cup of the warm heavy cream. Whisk together until combined. Now, whisking constantly, pour the egg yolk/cream mixture back into the saucepan.  Whisking constantly, cook the mixture until smooth and thickened, about 3 minutes or until it registers 160°F on a candy/oil thermometer. (I usually don’t measure the temperature, but you can if desired.)
4. Remove from heat and stir in the vanilla extract. Set aside.
5. Melt chopped chocolate in a double boiler or the microwave. If using the microwave: place the chocolate in a medium heat-proof bowl. Melt in 20 second increments in the microwave, stirring after each increment until completely melted and smooth. Stir melted chocolate into the egg yolk mixture. Set aside.
6. Using a hand mixer or a stand mixer fitted with a whisk attachment, whip the remaining 1 and 1/4 cups (300ml) heavy cream on medium-high speed until medium peaks form, about 3-4 minutes. Medium peaks are between soft/loose peaks and stiff peaks. Pour in the chocolate/egg yolk mixture and using a spoon or rubber spatula, gently fold together. Avoid over-mixing which can deflate the mousse. Makes 4 cups chocolate mousse.
7. Spoon a heaping Tablespoon of graham cracker crumbs into the bottom of a 6-ounce (or larger) glass, custard cup, ramekin, parfait glass, bowl, etc. Spoon 1/3 cup chocolate mousse on top. Spoon another heaping Tablespoon of graham cracker crumbs on top, then another 1/3 cup of chocolate mousse. Repeat with 5 remaining parfaits. Each parfait has 2/3 cup of mousse and 2-3 Tablespoons of graham cracker crumbs.
8. Chill for at least 3 hours and up to 1 day. If chilling longer than 3 hours, cover each with plastic wrap or aluminum foil.
9. Place egg whites, sugar, and cream of tartar in a heatproof bowl. Set bowl over a saucepan filled with two inches of simmering water. Do not let it touch the water. (You can use a double boiler if you have one.) Whisk constantly until sugar is dissolved and mixture has thinned out, about 4 minutes. Remove from heat. Add the vanilla extract, then using a handheld or stand mixer fitted with a whisk attachment, beat on high speed for 5 minutes until stiff glossy peaks form.
10. Spoon marshmallow cream on top of each chilled mousse cup. If desired, use a large piping tip instead. I used Ateco round piping tip 808. Serve immediately or store in the refrigerator, uncovered for 1-2 hours. If desired, toast the marshmallow topping with a kitchen torch just before serving.
11. Cover and store leftover mousse cups in the refrigerator for up to 1 day.