This recipe is also in my ‘Celebrate with Kim-Joy’ book.
For the pâte à bombe mousse layer:
This makes the best, silky and rich chocolate mousse. This recipe makes more than you need for the terrarium, but this is a good thing as you will have extra to serve in little dishes, along with leftover cake.
600ml cream
1 tsp almond extract
9 medium egg yolks
270g caster sugar
70ml water
300g dark chocolate, roughly chopped
1 / whip the cream and almond extract in a stand mixer or use a handheld electric whisk) fitted with the balloon whisk attachment to soft peaks. Chill in the fridge for now.
2 / Place the egg yolks in a stand mixer and whisk until fluffy and pale. Meanwhile, add the sugar and water to a pan and heat over a high heat unfill redches 120°C (248°F] (try to time the egg yolks finishing whisking at a similar time to the sugar syrup reaching temperature - you can always slow the beaters if necessary). Pour the 120°C (248°F) sugar syrup onto the egg yolks while whisking on medium speed, then increase the speed to high and whisk until the bottom of the bowl is cool to touch: this is
your pâte à bombe.
3 / Meanwhile, melt the chocolate in a heatproot bowl set over a pan of gently simmering water, makina sure the base of the bowl doesn't touch the water. Once melted. leave the chocolate to cool to room temperature, then fold it into the cooked pâte à bombe. It will go quite thick and look uneven, but that's normal. Carefully fold in the almond cream in 3 stages, being careful not to knock out the air.
4 / add to the base of your terrarium serving dish. Then chill for at least 4 hours. The mousse is sturdy before chilling, so you could layer everything up, then cover and chill it all together overnight before serving.
For the Chocolate Cake layer:
The ultimate chocolatey, moist chocolate cake. Don't skip adding the boiling water at the end - this makes the batter very liquidy (that's normal!) and helps dissolve the cocoa powder and incorporate it into the batter.
The extra moisture also helps to produce a soft and unbelievably moist cake. The coffee adds depth of flavour to the chocolate, but the actual coffee flavour will be undetectable, so don't worry if you're not a coffee fan! This cake is very soft and moist. Perfect to go with the creamy mousse in the terrarium.
MAKES: 2 x 18cm cakes/ or you can bake this in muffin tins like I did in the video (this makes more cake than you need for the terrarium, but it’s always good to have extra)
125ml vegetable oil
150ml whole milk, at room temperature or warmed in the microwave for 1 minute
3/4 Tbsp lemon juice
325g caster sugar
220g plain flour
1tsp baking powder
1tsp bicarbonate of soda
1/2tsp salt
65g unsweetened cocoa powder
65g sour cream (or whole yogurt)
1/2 tbsp vanilla bean paste
3 medium eggs
1/2tbsp instant coffee granules (you can't taste the coffee, but leave it out if you're coffee averse£
220ml boiling water
1 / Preheat the oven to 160°C fan. Grease 2 x 18-cm cake tins and line the bases with a circle of baking paper (or use muffin tins with muffin liners).
2 / Put the milk into a large bowl and squeeze in the lemon juice. Set aside for now.
3 / Mix the sugar, flour, baking powder, bicarbonate of soda, salt and cocoa powder in a separate bowl.
4 / Add the sour cream, vegetable oil, vanilla and eggs to the milk mixture. Whisk to break up the eggs. The oil will separate, but that's fine.
5 / Put the coffee granules into a heatproof bowl/cup/pouring jug and pour in the boiling water. Stir and set aside.
6 / Pour the liquid mixture onto the dry ingredients and whisk until partially mixed. Add the hot coffee and whisk again until everything is combined. Divide the batter between the prepared tins (or muffin tins) and bake for 30-40 minutes (less for muffins) or until a skewer inserted into the centre of a cake comes out without any wet batter on it. Leave to cool in the tins for 10 minutes before turning out onto a wire rack, peeling off the baking paper and leaving to cool completely.
7 / let the cake cool. Then they’re ready to be assembled in the terrarium!
For the buttercream cacti:
150g salted butter, softened/room temp
300g icing sugar
1tsp vanilla
1/2tbsp milk
1 / whisk together butter, icing sugar and vanilla until fluffy. Add milk to soften icing. You want to keep it somewhat stiff to help with piping.
2 / use various food dyes to colour the buttercream, and pipe with different piping tips to create your cacti (see the video). I used a leaf piping tip, an open star piping tip, and ruffle piping tip. You need to chill your cacti before placing inside the terrarium.
The cookie decorating is a whole separate thing and I’ll do a separate post on that.
Assemble in your terrarium like in the video! Mousse (then chill at this stage, or right at the end after layering everything), then cake, then cactus and cookies. I used a bowl at the base of my terrarium just because my terrarium was so deep and I needed to build some height without putting tons of mousse in and messing up the ratios.
You can do different versions of this. Here is a previous (different!) edible terrarium I made:
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