No-Bake Chocolate Hazelnut Mousse Cake Bars Recipe

If you have a soft spot for creamy, chocolatey desserts that don’t require baking, you’re going to absolutely adore these No-Bake Chocolate Hazelnut Mousse Cake Bars. Imagine layers of rich chocolate biscuit base, a silky milk chocolate mousse swirled with crunchy hazelnuts, all crowned with a glossy dark chocolate ganache speckled with roasted hazelnuts. They’re elegant, indulgent, and perfect for impressing guests or treating yourself on any occasion—without turning on your oven.

this Recipe

Ingredients You’ll Need

The magic of these No-Bake Chocolate Hazelnut Mousse Cake Bars lies in a handful of straightforward ingredients that come together effortlessly. Every component has a clear role, from the crumbly chocolate biscuit base that adds structure and crunch, to the creamy mousse and decadent ganache that provide layers of smooth, nutty flavor.

• Chocolate biscuits (200g): Choose chocolate cookies like Oreos without the filling, for a sturdy and flavorful base.
• Melted butter (80g): This binds the biscuit crumbs into a compact crust with a luscious mouthfeel.
• Milk chocolate (200g): Use good quality for a creamy, sweet milk chocolate mousse layer that melts in your mouth.
• Gelatin powder (2 tsp) and water (3 tbsp): Essential to gently set the mousse to hold its shape without baking.
• Heavy cream (400ml total): Cold cream whipped to soft peaks forms that light, airy texture in the mousse and ganache.
• Crushed hazelnuts (100g, optional): Adds delightful crunch and nutty depth to the mousse.
• Dark chocolate (150g): Provides a rich, bittersweet finish in the ganache topping.
• Chopped roasted hazelnuts (50g): Sprinkled in the ganache for extra texture and a toasty note.

How to Make No-Bake Chocolate Hazelnut Mousse Cake Bars

Step 1: Create the Chocolate Biscuit Base

Start by crushing your chocolate biscuits into fine crumbs—using a food processor makes this quick and uniform, but a ziplock bag and rolling pin work in a pinch. Mix the crumbs thoroughly with melted butter until all the crumbs are moistened evenly. Press this mixture firmly and evenly into the bottom of a lined square or rectangular pan; this forms the foundation for your mousse. Pop it into the fridge to chill for about 20 minutes so it sets into a firm base.

Step 2: Make the Milk Chocolate Mousse

While the base chills, prepare your mousse. Sprinkle gelatin powder over water and let it bloom for 5 to 10 minutes—this step is key for that perfect mousse texture. Next, gently melt your milk chocolate, either in a double boiler or carefully in bursts in the microwave. Warm the gelatin until it’s fully dissolved, making sure it doesn’t boil, and blend it smoothly into the melted chocolate. Then, whip your heavy cream until soft peaks form—this airy addition will transform the dense chocolate into fluffy mousse. Fold the whipped cream delicately into the chocolate mix, preserving that lightness, and stir in the crushed hazelnuts if you love a bit of crunch. Pour this luscious mousse over your chilled base, smooth the surface with a spatula, and refrigerate for 2 to 3 hours to set.

Step 3: Prepare the Decadent Ganache Topping

Once your mousse has set beautifully, it’s time for the crowning glory: the ganache. Warm your heavy cream just until it simmers, then pour it over chopped dark chocolate. Let it rest for a couple of minutes to soften the chocolate, then stir gently until glossy and smooth. Fold in the chopped roasted hazelnuts for texture and flavor, then pour the ganache over the mousse layer, smoothing it evenly. Refrigerate again for at least 2 hours so everything firms up just right.

Step 4: Chill and Slice with Care

After a good chill, your No-Bake Chocolate Hazelnut Mousse Cake Bars will be perfectly firm but buttery soft. Use a warm knife—run it under hot water and dry it each time—to get those clean, elegant squares without smudging the layers. Each bite offers a heavenly contrast of crunchy base, fluffy mousse, and silky ganache.

How to Serve No-Bake Chocolate Hazelnut Mousse Cake Bars

Garnishes

To elevate your presentation, sprinkle a few extra roasted hazelnuts or chocolate shavings right before serving. A dusting of cocoa powder or a drizzle of hazelnut syrup adds a touch of elegance and an extra hit of chocolate-hazelnut flavor that complements each bite wonderfully.

Side Dishes

These bars pair perfectly with a steaming cup of black coffee or a rich espresso. The bitterness of the coffee balances the creamy sweetness of the mousse, rounding out the indulgence beautifully. Alternatively, a small bowl of fresh berries can brighten the richness and add a fresh burst on the side.

Creative Ways to Present

For a special occasion, serve the bars on a decorative platter alongside edible flowers or fresh mint leaves. You can also cut them into bite-size squares and place them on cocktail picks for easy party bites. Layering the bars with a glass of chilled milk or a nutty liqueur creates a memorable dessert experience your guests will rave about.

Make Ahead and Storage

Storing Leftovers

Once made, these No-Bake Chocolate Hazelnut Mousse Cake Bars keep wonderfully in the refrigerator for up to 4 days when stored in an airtight container. The mousse and ganache maintain their texture, making them perfect for making ahead for gatherings or your own indulgent treat throughout the week.

Freezing

If you want to save them longer, you can freeze the bars for up to 2 months. Wrap them tightly with plastic wrap and place them in a freezer-safe container. When ready to enjoy, thaw them overnight in the fridge to keep the moist mousse and crisp base intact.

Reheating

These bars don’t need reheating—chilled is the way to go! Their creamy mousse and ganache are at their best when cool and firm. Just take them out of the fridge 10 minutes before serving to soften slightly for the best melt-in-your-mouth texture.

FAQs

Can I substitute gelatin for a vegetarian alternative?

Absolutely! You can use agar-agar as a plant-based substitute, but be sure to follow its specific instructions for blooming and dissolving since it behaves differently than gelatin.

What if I don’t have roasted hazelnuts?

You can use raw hazelnuts and toast them yourself in a dry pan over medium heat for a few minutes until fragrant and golden. Alternatively, chopped almonds or pecans make great nutty substitutes.

Can these bars be made gluten-free?

Yes! Substitute the chocolate biscuits with gluten-free chocolate cookies or crushed gluten-free graham crackers to keep the base safe for gluten intolerance without sacrificing flavor.

Is it possible to make the mousse chocolate-free?

To keep the spirit of these bars, chocolate is essential, but for a twist, you could try a vanilla or coffee-flavored mousse instead. Just note it will change the classic No-Bake Chocolate Hazelnut Mousse Cake Bars experience.

How do I ensure smooth ganache every time?

Make sure the cream is hot but not boiling when poured over the chocolate, and stir gently and slowly until completely smooth. Using finely chopped chocolate also helps it melt evenly for a glossy finish.

Final Thoughts

Making No-Bake Chocolate Hazelnut Mousse Cake Bars is like creating a little chocolate masterpiece from scratch with minimal effort. Each step is incredibly rewarding, and the result is a show-stopping dessert that combines textures and flavors in the most delightful way. If you’re looking for a crowd-pleaser that’s simple yet sophisticated, you really can’t go wrong with this recipe. Go ahead, treat yourself and your loved ones to a batch—you’ll be so glad you did!