Decadent Chocolate Mousse Brownies

These decadent chocolate mousse brownies combine a rich, fudgy brownie base with a light, silky chocolate mousse topping. The contrast in texture makes them feel luxurious while still being very achievable for a home baker. This is a medium-difficulty bake that feels impressive but uses straightforward techniques. From start to finish, you will need around 1 hour 30 minutes including chilling time.

Ingredients

For the brownie base

• 200 g dark chocolate, finely chopped
• 150 g unsalted butter
• 150 g caster sugar
• 100 g light brown sugar
• 3 large eggs, at room temperature
• 1 tsp vanilla extract
• 100 g plain flour
• 30 g cocoa powder
• 0.5 tsp fine sea salt

For the chocolate mousse topping

• 200 g dark chocolate, chopped
• 300 ml double cream
• 2 tbsp icing sugar
• 1 tsp vanilla extract

For finishing

• Cocoa powder or chocolate curls, for dusting

Method

Oven preparation

Preheat the oven to 180°C, 160°C fan. Line a 20 cm square tin with baking parchment, making sure the sides are well covered for easy lifting later.

Mixing the brownie batter

Melt the dark chocolate and butter together gently in a heatproof bowl set over simmering water, or in short bursts in the microwave. Stir until smooth, then leave to cool slightly.

Whisk the caster sugar, brown sugar, eggs, and vanilla in a large bowl until glossy and well combined. Pour in the cooled chocolate mixture and mix gently until smooth.

Sift in the flour, cocoa powder, and salt. Fold carefully until just combined, taking care not to overmix.

Baking

Pour the batter into the prepared tin and level the surface. Bake for 25 to 30 minutes until the top looks set but the centre still has a slight wobble. This ensures a fudgy texture.

Leave the brownies to cool completely in the tin.

Preparing the mousse

Melt the dark chocolate for the mousse and set aside to cool to room temperature. Whip the double cream with icing sugar and vanilla until soft peaks form.

Gently fold the cooled melted chocolate into the whipped cream until smooth and airy.

Assembling

Spread the chocolate mousse evenly over the cooled brownie base. Chill in the refrigerator for at least 1 hour until the mousse is set. Dust lightly with cocoa powder or decorate with chocolate curls before slicing.

Tips

Why did my brownies turn out dry?

Overbaking is the most common cause. Remove them from the oven while the centre is still slightly soft, as they will firm up as they cool.

How do I keep the mousse light and airy?

Make sure the melted chocolate is cool before folding it into the cream. Warm chocolate will deflate the mousse.

Can I get clean slices?

Chill the brownies well and use a sharp knife wiped clean between cuts for neat edges.

Serving Suggestions

• Serve chilled with fresh raspberries
• Add a dollop of lightly whipped cream on the side
• Pair with strong coffee or espresso

Storage

Room temperature

Not recommended due to the mousse topping.

Refrigerator

Store in an airtight container for up to 3 days. Keep chilled until ready to serve.

Freezing

Freeze the brownie base only, well wrapped, for up to 2 months. Add the mousse topping fresh after thawing.

Nutrition

• Calories: 420 kcal
• Carbohydrates: 38 g
• Protein: 5 g
• Fat: 28 g
• Saturated Fat: 16 g
• Sodium: 120 mg

Nutritional values are estimates and may vary based on ingredients used.

FAQs

Can I use milk chocolate instead of dark chocolate?

Dark chocolate is recommended for balance. Milk chocolate will make the brownies and mousse noticeably sweeter.

Do these brownies need to be kept chilled?

Yes, the mousse topping requires refrigeration to stay set and safe to eat.

Can I make these a day ahead?

Yes, they are ideal for making ahead. The flavour improves after chilling overnight.

What tin size works best?

A 20 cm square tin gives the best thickness for both brownie and mousse layers.

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