Chocolate Hazelnut Mousse Tart

Necessity is the mother of invention, so they say. One moody Sunday, as the heavens poured, I decided I was in need of some comfort baking.

In my kitchen, I found marshmallows and whipping cream left over from previous bakes. In the pantry, there was a jar of Nutella I’d bought on a whim a week ago, and a couple bars of chocolate that I always make sure to have at hand.

Rifling through my recipe notebook, I soon realised I had the wherewithal for a chocolate mousse. Not a real mousse set with eggs, but a cheaty version that uses marshmallows as the setting agent. I also had Nutella that was crying out to be part of the action.

But why not take it one step further? I decided to make a chocolate tart as well. Again, not a real pastry tart, but one made of pulverised biscuits like a cheesecake base. And that’s how this decadent chocolate hazelnut mousse tart was born.


For the tart shell:

  • 250g digestive biscuits (about 17 biscuits)
  • 50g hazelnuts (opt.)
  • 125 butter, melted
  • 2 tbsp caster sugar
  • 2 tbsp unsweetened cocoa powder

For the chocolate hazelnut mousse:

  • 150g mini marshmallows
  • 100g dark chocolate (70% cocoa solids)
  • 200g Nutella or any other chocolate hazelnut spread
  • 1/4 cup water
  • 1/2 tsp salt
  • 1 cup double/whipping cream

Makes one 9-inch tart.


Step 1: Preheat your oven to 175°C (350°F). Grease and flour a 9-inch fluted tart pan (or use an equivalent spray).

Step 2: Dump the digestive biscuits (and hazelnuts, if you’re using them) in a resealable plastic bag. With a rolling pin, pulverise the biscuits into a fine rubble. (You can use a food processor if you have one.)

Step 3: In a bowl, mix together the melted butter, sugar, cocoa, and ground-up biscuits. Press this damp sandy mixture into the tart pan. Take your time to get an even layer over the bottom and up the sides of the pan, pressing down as firmly. You will lose a few crumbs over the side, but focus on getting a strong tart shell. Use the back of a spoon to help you smooth out the tart shell.

Step 4: Bake the tart shell for 15 minutes. Set aside to cool.

Step 5: Add the marshmallows, chocolate, Nutella, water, and salt to a saucepan and melt slowly over low heat. Set aside to cool.

Step 6: While the chocolaty mixture is cooling, whip the cream until thick and stiff. When the chocolaty mixture has cooled to room temperature, add to the whipped cream and fold to combine. (If the mixture is too warm, it’ll melt the whipped cream.)

Step 7: Pour the mousse into the cooled tart shell. Refrigerate for at least 2 hours to allow the mousse to set.

This mousse never sets hard. Instead, it becomes a voluptuously creamy filling that just about holds its shape when sliced into. Thin slices only please – this tart is really that rich.

You’ll also realise my penchant for thick crusts. I think it balances out the rich filling, and I’m always paranoid of the tart falling apart if the shell is too thin. However, if you’d like something more elegant and refined-looking, you can always reduce the tart shell ingredients by 25%.

Another great way of making this recipe infinitely simpler is to buy a pre-made tart shell – that way there’s no baking involved at all and all you have to do is whip up the mousse!

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