Triple Chocolate Mousse Cake

A bowl of chocolate mousse is a decadent treat, but a layered chocolate mousse cake with a cookie crust is next-level. There are many varieties of chocolate mousse cake. Some have chocolate cake crusts rather than the cookie crust; others are chocolate cake layered with a mousse frosting. But we think our double-layered chocolate mousse cake is one of the best.

This mousse cake is set in the refrigerator rather than baked and is served cold. The texture and flavor are dreamy — an ethereal light and fluffy chocolate dessert.

To add contrasting flavor and keep the thick mousse layer from becoming too monotonous, we developed an easy method for creating a two-toned mousse.

• Milk chocolate layer: The milk chocolate layer is slightly sweeter and more subdued.
• Dark chocolate layer: This richer layer is made with dark chocolate. Dark chocolate balances out the sweetness of the milk chocolate layer with its intense chocolate flavor.
• Oreo crust: A classic no-bake Oreo crust that’s sure to hit the spot for chocolate fans.

There are many ways to get that beautiful light and airy texture in chocolate mousse. Traditionally in French cooking, mousse is thickened with both egg whites and yolks. While it’s a decadent and absolutely wonderful way to prepare mousse, the procedure is a bit more complicated and the eggs are usually raw, which means not everyone will be comfortable digging in. Instead, we opted for folding melted chocolate and gelatin into whipped cream.

• Use gelatin powder.  Incorporating gelatin powder into the chocolate mixture, along with folding in whipped cream gives the chocolate mousse a light and airy texture. Gelatin powder also stabilizes and sets the chocolate mousse when refrigerated.
• Allow the chocolate mixture to cool. Make sure the dark and milk chocolate mixtures are cooled to room temperature before folding in the whipped cream, otherwise the whipped cream will melt.
• Gently fold the whipped cream into the chocolate. Folding is a mixing technique where you gently combine two ingredients without stirring. Using a flexible spatula, swipe the whipped cream down under the chocolate, then scoop it up and over until just combined. It’s a swoop and tuck motion that’s used in desserts like classic chocolate mousse and sponge cake.

Delicate and light, the perfect slice of chocolate mousse cake is only achieved by cutting it with a warm knife. Sure, you can get a “good enough” slice without warming the knife, but here is how to get one that looks just like our pictures.

1. Fill a tall bowl or glass with hot water. It should be big enough to fit the blade of a chef’s knife.
2. Place the blade of the knife in the hot water. Keep it in there for a good 10 to 30 seconds until the blade is hot.
3. Wipe excess water off with a towel and slice into the cake. In between each cut, return the knife to the warm water and wipe it off with a towel again before going in to slice.