Directions

1. 1

   Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper, allowing it to overhang slightly on the sides for easy removal.

2. 2

   In a food processor, combine the flour and 6 Tbsp softened butter. Pulse 8–10 times until the mixture resembles coarse crumbs and is just combined. Do not overprocess.

3. 3

   Press the crust mixture evenly into the bottom of the prepared pan, using your fingers or the back of a measuring cup to create a compact layer.

4. 4

   Bake the crust for 20–22 minutes until it is light golden brown. Remove from the oven and let cool completely on a wire rack.

5. 5

   While the crust cools, finely chop the bittersweet chocolate and melt it using a double boiler or in 30-second intervals in the microwave at medium power, stirring between intervals until smooth. Set the melted chocolate aside.

6. 6

   Pour the heavy cream into a bowl and beat with an electric mixer or whisk until stiff peaks form. Transfer to a separate small bowl, cover, and refrigerate.

7. 7

   In the bowl of a stand mixer, combine the eggs, sugar, and water. Beat on medium-high speed for about 6 minutes until the mixture becomes pale yellow and slightly thickened.

8. 8

   Create a double boiler by placing the mixer bowl over a saucepan of gently simmering water. Whisk the egg mixture occasionally while heating until it reaches an internal temperature of 160°F (71°C)—this pasteurizes the eggs for food safety.

9. 9

   Return the bowl to the stand mixer and beat on medium speed for approximately 8 minutes, until the mixture has cooled to room temperature and has thickened to a mousse-like consistency.

10. 10

    With the mixer still running, pour in the melted chocolate and vanilla extract, beating until fully incorporated and the mixture is smooth.

11. 11

    Add the remaining 6 Tbsp butter to the mixer one tablespoon at a time, beating on medium speed until each piece is fully incorporated and the filling is creamy and smooth.

12. 12

    Remove the bowl from the mixer. Using a spatula, gently fold the chilled whipped cream into the chocolate mixture in two additions until no white streaks remain.

13. 13

    Pour the chocolate mousse filling over the cooled crust and use an offset spatula to smooth the top evenly. Cover with plastic wrap and refrigerate for at least 3 hours, or until the filling is firmly set.

14. 14

    For the topping: In a small bowl, sprinkle the gelatin over 2 Tbsp water and let it soften for 2 minutes.

15. 15

    Microwave the gelatin mixture for 15 seconds, then whisk until the gelatin is completely dissolved and clear.

16. 16

    In a clean bowl, beat the remaining heavy cream (reserve from before step 6, or use 1 cup fresh cream) to soft peaks. While beating, slowly drizzle in the dissolved gelatin mixture, then add the powdered sugar, and continue beating until stiff peaks form.

17. 17

    Spread or pipe the whipped cream topping evenly over the chilled chocolate layer. Refrigerate until the topping is set, at least 1–2 hours.

18. 18

    Cut into 16 squares (4x4 grid) and serve chilled. Decorate with chocolate sprinkles, curls, or a dusting of cocoa powder if desired. Store covered in the refrigerator for up to 5 days.