Line the base of a springform pan (6" or 8") with parchment paper. Lightly grease the sides or line them with acetate for extra-smooth edges.

Mix 1 cup of chocolate cookie crumbs with 3 tablespoons of melted butter until the texture resembles wet sand.

Press the mixture firmly into the bottom of the pan to form a compact, even crust.

Chill the crust in the fridge while you prepare your first mousse layer.

Pro Tip: Use the bottom of a measuring cup or glass to pack the crust firmly—it helps prevent crumbling when slicing later.

Bloom the gelatin: Sprinkle 1 tsp gelatin over 1 tbsp cold water. Let it sit for 5 minutes.

Melt 4 oz dark chocolate in a heatproof bowl over simmering water or in the microwave in short bursts.

In a small saucepan, heat ¼ cup heavy cream just until warm. Stir in the bloomed gelatin until dissolved.

Add the gelatin-cream mix to the melted chocolate and stir until smooth and glossy.

Whip the remaining ½ cup cream until soft peaks form. Gently fold into the chocolate mixture until well combined.

Pour over the chilled crust and level the surface with a spatula. Chill for 30–45 minutes until set.

Follow the exact same steps using milk chocolate. Allow the dark chocolate layer to firm up completely before adding the milk chocolate mousse. This ensures crisp, defined layers in your final slice.

Tip: Gently spoon the mousse over the previous layer, then spread it evenly to avoid disturbing the base.

Repeat the mousse process again with white chocolate, being extra careful while melting—white chocolate is more sensitive to heat.

Pour over the milk chocolate layer once it’s firm, smooth the top, and chill the cake for at least 4 hours, or preferably overnight.

Once fully set:

Run a warm knife along the inside of the pan and carefully remove the springform ring.

Transfer the cake to a serving plate or cake stand.

Decorate as desired with chocolate shavings, a drizzle of ganache, or fresh berries for a pop of color.

Always let each mousse layer chill and set before adding the next.

Use room-temperature chocolate when mixing with gelatin for smooth blending.

For clean slices, dip your knife in hot water and wipe between cuts.

Want to save time? You can skip the crust—just pour mousse directly into the pan and layer as usual!

This stunning layered mousse dessert is not only beautiful—it’s surprisingly forgiving. Whether you’re making it for a birthday, dinner party, or just to treat yourself, this cake will always impress.