Preheat the oven to 325°F. Spray a 10-inch springform pan with cooking spray.

Cut the butter into tablespoon-sized pieces. In a microwave-safe bowl, combine the butter and chopped chocolate. Microwave for 1 minute, stirring every 15 seconds until melted.

Add the sugar, vanilla, and salt to the melted chocolate mixture. Whisk until well combined.

Add the eggs one at a time, whisking each until fully blended.

Gently fold in the gluten-free baking flour until everything is smoothly mixed.

Pour the batter into the prepared pan and smooth it out. Bake for 30-35 minutes or until a toothpick comes out clean.

Once baked, cool the cake on a wire rack. Ensure it cools completely before adding the mousse.

In a small microwave-safe bowl, melt 8 ounces of chopped chocolate (microwave for 1 minute, stirring every 15 seconds).

In a mixing bowl, combine the melted chocolate with powdered sugar, cream cheese, and vanilla. Mix until the texture is completely smooth.

With the mixer on low, gradually add in the heavy cream. Scrape the bowl's sides and bottom, then increase the speed to medium-high. Whip the mixture until it becomes fluffy, about 3-4 minutes.

Spread the mousse evenly on top of the cooled chocolate cake. Cover and refrigerate for at least 6 hours or overnight.

In another mixing bowl, whip together the heavy whipping cream, powdered sugar, and vanilla until stiff peaks form (about 4-5 minutes).

Spread the whipped cream over the mousse layer and garnish with grated chocolate, if desired.

Run a thin knife around the cake’s edge before carefully opening the springform pan. Slice and enjoy!