Make the Chocolate Mousse

Step 1

• Bring 1 inch of water to a simmer in a small saucepan over medium-low.
• Place a medium-size heatproof bowl over the pan; add chopped chocolate and butter. (Make sure the bottom of the bowl does not touch water.)
• Cook, stirring occasionally and adjusting heat as needed to maintain a simmer, until mixture is smooth, 3 to 5 minutes.
• Remove chocolate mixture from heat; let cool, uncovered, at room temperature until just warm to the touch, about 10 minutes.
• Reduce heat to low and keep water in the saucepan at a bare simmer.

Step 2

• Meanwhile, whisk together egg yolks and 2 tablespoons granulated sugar in the bowl of a stand mixer.
• Place bowl over saucepan of simmering water, whisking constantly, until mixture registers 160°F on an instant-read thermometer.
• Remove bowl from heat; transfer to a stand mixer fitted with the whisk attachment. Beat on medium-high speed until the mixture is very pale yellow in color, thick, and fluffy, about 3 minutes.
• Fold egg yolk mixture into cooled chocolate mixture.

Step 3

• In a clean bowl of stand mixer fitted with the whisk attachment, beat egg whites on medium-high speed until foamy, about 15 seconds.
• Gradually add remaining 2 tablespoons granulated sugar in a slow, steady stream, beating on medium-high speed until stiff peaks form, 1 to 2 minutes.
• Using an electric mixer or whisk, beat cream in a separate medium bowl until medium peaks form.
• Fold egg white mixture into chocolate mixture in three additions.
• Fold in whipped cream just until mixture is combined and no dark or white streaks remain.
• Add in the FSHO. Each line on the dablicator equals 55mg per dose. This recipe cuts 10 slices making the total dosage about 100mg for the whole cake, or 10mg per slice. Twist the bottom of the applicator until you get to two clicks. Press the plunger. Mix until combined.
• Cover and chill for at least 8 hours or up to 24 hours.
• Bring to room temp before applying mousse.

Make the Cake Layers

Step 1

• Preheat the oven to 350°F.
• Coat three 9-inch round cake pans with baking spray; line bottoms with parchment paper. Lightly spray parchment with baking spray.

Step 2

• Sift together flour, cocoa, baking soda, and baking powder in a large bowl; whisk in salt until combined. Set aside.
• Beat eggs with a stand mixer fitted with the whisk attachment on medium-high speed until light and foamy, about 2 minutes.
• Gradually add granulated sugar; beat on medium-high speed until very pale and voluminous, about 5 minutes, scraping down sides of bowl as needed. (Mixture should fall off whisk attachment in ribbons and remain suspended briefly on the surface before sinking back into the batter.)
• With the mixer running on low speed, add flour mixture in three additions alternately with coffee and melted butter, beginning and ending with flour mixture; beat until nearly combined, stopping to scrape down sides of bowl as needed.
• Add crème fraîche; beat on low speed just until combined, about 30 seconds, folding by hand toward end if needed. (Batter may look slightly broken but will bake just fine.)

Step 3

• Divide batter evenly among prepared baking pans (about 3 cups per pan); tap baking pans a few times on the work surface to evenly spread batter and eliminate any air bubbles.
• Bake in a preheated oven until a wooden pick inserted in the center of the cakes comes out clean, 25 to 30 minutes.
• Let cake layers cool in baking pans on wire racks for 10 minutes; remove cakes from baking pans and let cool completely, parchment side down, on racks, 1 hour and 30 minutes to 2 hours.

Make the Icing

Step 1

• Sift together powdered sugar and cocoa in a medium bowl. Set aside.
  Beat butter with a stand mixer fitted with the paddle attachment on medium speed until creamy, about 2 minutes.
• Gradually add powdered sugar mixture, beating on low speed just until combined, about 2 minutes, scraping down sides of bowl as needed.Increase mixer speed to medium and beat until fluffy, 2 to 3 minutes.
• Gradually add cream and vanilla, beating on medium-low speed until combined and stopping to scrape down sides of bowl as needed.
• Spoon 1 cup icing into a piping bag or ziplock plastic bag; cut a 1/2- to 3/4-inch hole in the corner. Leave the remaining icing in the bowl.

Assemble the Cake

Step 1

• Trim cakes flat using a cake leveler or serrated knife, if necessary; discard parchment. Place one cake layer on a cardboard cake round or plate.
• Pipe a 1/2-inch-tall border of icing around the edge of the first cake layer.
• Spoon half of chocolate mousse (about 2 cups) onto the center of the cake, and spread evenly within the border using a small offset spatula.
• Top with a second cake layer, cut side down, and repeat the process with remaining chocolate mousse.
• Top with a third cake layer, cut side down.
• Spread remaining icing over top and sides of cake.
• Chill until set, about 15 minutes.

OPTIONAL: Tips for Making Ahead

Cooled cake layers can be made up to 1 day in advance. Wrap layers in plastic wrap and refrigerate. Frosting can be stored in an airtight container in the refrigerator 1 day ahead; bring to room temperature before assembling the cake.