Divine chocolate mousse

If you had stopped by this time last weekend, you would have found me sitting on our living room floor, surrounded by three dirty bowls, and a fourth bowl filled with a pathetic amount of (unwhippable) whipping cream. Things weren't going so well.

Let's get the obvious questions out of the way:

Why the living room?  
Or rather, why not the kitchen? Excellent question. The only electrical outlet in our entire kitchen is located behind the sink cabinet. We ran a power bar out the bottom of the cabinet, but the fridge, toaster oven and vitroceramic hob (it sounds so much more impressive than it really is) make quick work of the available outlets. Fortunately, our "living room" is mere steps from our "kitchen." It's all very open concept.
Why sitting on the living room floor?
OK, so we've relocated to the living room. Why not stand up in the living room, you ask? Again, an excellent question. For the answer, we need to consider cord length. Specifically, how the tiny one on this genius little multipurpose device doesn't reach from the electrical outlet near the floor to the tabletop. Hooray for low-lying coffee tables.
Why so many bowls?
Let me assure you that it's not because I like to do dishes. The first three just didn't work out for whipping cream. It was a bit of a "Goldilocks" situation: one bowl was too warm, one bowl was too small...and one bowl was too plastic-y.
Why bother?
Because it was step 4 of 5 of what turned out to be the most divine chocolate mousse I've ever tasted. The IKEA chocolate mousse I've posted before is all fine and well when time and patience aren't on your side, but this—this is what you make when you want to kick dessert up a notch. If that last mousse was IKEA, this one's Muji.
Chocolate Mousse
Pastry cream:
3 egg yolks (save the whites for the chocolate meringue below)
50 grams white sugar
20 grams cornstarch
250 millilitres whole milk
1 heaping tablespoon unsweetened cocoa powder

3 egg whites (the ones you set aside earlier)
50 grams icing sugar
Few drops of lemon juice
Pinch of fine salt
150 grams semi-sweet chocolate, chopped finely
200 millilitres whipping cream
Step 1: Prepare the pastry cream. In a medium-sized heatproof bowl, whisk together the egg yolks and sugar until the mixture is pale and thick. Add the cornstarch and whisk until smooth.

In a medium saucepan, combine the milk and cocoa powder. Bring the mixture to a boil, stirring occasionally, then switch off the heat.

Pour the hot cocoa mixture into the egg mixture in a slow stream, whisking vigorously the entire time to stop the eggs from scrambling. Don't worry—you've got this! If you start to freak out, take a pause from the pouring and keep whisking until you're ready to give it another go.

Wash and dry the saucepan you just used to heat up the milk and cocoa. Now put the mixture you've just created into the saucepan over medium heat. Keep whisking all the time—and don't forget to scrape the sides and bottom of the saucepan from time to time to prevent burning.
The mixture will slowly start to thicken and eventually begin to bubble. Once the pastry cream releases a bubble or two, immediately remove the saucepan from the stovetop and scrape the mixture into a shallow bowl. 
Press microwave-safe plastic wrap onto the surface of the pastry cream, up the insides of the bowl and down the outside. Refrigerate the mixture for at least one hour.

Step 2: Melt the finely chopped chocolate in the top of a barely simmering double boiler.
Step 3: While the pastry cream is chilling and the chocolate is melting, tackle the meringue. Put half of the egg whites into a clean glass or metal bowl. Add the sugar, lemon juice and salt, then whisk until the mixture is white and frothy. You might want to switch to electric beaters at this point. Add the rest of the eggs whites and continue whisking until the meringue forms stiff peaks when the whisk is removed.
Step 4: Whip the cream until soft peaks form.

Step 5: Assemble the mousse. Remove the chilled pastry cream (step 1) from the fridge. Beat it briefly to remove any lumps, then stir in the melted chocolate (step 2). Mix in one-third of the meringue (step 3), then gently fold in the rest. Last but not least, gently fold in the whipped cream (step 4). Divide the mousse between 4-6 glasses or ramekins, or go family-style with a single, large bowl. Either way, chill the mousse for at least an hour before serving.

Source: Barely adapted from Rachel Khoo's chocolate mousse with cocoa nibs.

Notes: Rachel's original recipe calls for lining the serving glasses or ramekins with softened butter and cocoa nibs, and sprinkling additional cocoa nibs on top before serving. I didn't have any kicking around, so I opted for a classic mint garnish instead. She recommends eating the mousse the same day it's made, and advises keeping it no longer than two days due to the raw egg whites.