These Chocolate Orange Mousse Cups have an deliciously light and airy texture with a deep chocolate flavour and bright pop of orange. It is a perfect make-ahead dessert to prepare for a fancy dinner party or special occasion.
Finely chop the chocolate and place in a large heatproof bowl. Melt until completely smooth, either over a double-boiler (see note 1) or in the microwave in 30 seconds increments.
Add the cubed butter a few pieces at a time, gently stirring until completely melted. The temperature of the chocolate should have dropped.
Mix in the orange juice and orange zest. Stir until completely combined.
Separate the large egg yolks from the egg whites. Place the egg yolks in the chocolate mixture and the egg whites in a large clean bowl (if using a hand mixer) or bowl of a stand mixer fitted with the whisk attachment.
Stir the egg yolks into the chocolate mixture until fully combined (see note 2) Set aside.
Add the salt to the egg whites and start whipping on medium speed. Once you reach soft peaks (the eggs will have turn white, almost doubled in volume and reach the consistency of shaving cream), start adding the sugar about one or two tablespoons at a time while continuously whisking.
When all the sugar has been incorporated, increase the speed to high. Keep on whipping the egg whites until you reach stiff peaks. The meringue should have tripled in volume, be white and glossy and hold its shape on the whisk.
Add about a quarter of the whipped egg whites into the chocolate mixture. Using a whisk, very gently mix it in until you can't see any white (see note 3).
Switch to a spatula and continue to very gently fold in the rest whipped egg whites in three or four times. Stop folding as soon as all the egg whites have been incorporated and you cannot see any streaks of white anymore.
Carefully pour the orange chocolate mousse into dessert cups. Gently shake the filled cups to evenly distribute the mousse, then place in the fridge to chill for at least 4 hours, preferably overnight.
Whipped Cream (optional)
Before serving, optionally prepare the toppings.Place the cold cream in a large bowl (or bowl of a stand mixer fitted with the whisk attachment) and sift in the icing sugar. Whisk on medium speed until the cream starts to thicken, then slowly increase to high speed until you reach stiff peaks.
Place a large dollop of whipped cream (or pipe over the cream using a piping bag fitted with a star shaped or round nozzle) over the set chocolate orange mousse.
Top with some fresh orange zest and shaved chocolate before serving.
Notes
To make a double-boiler: place the chopped chocolate in a heat-proof bowl that is slightly larger than a medium size saucepan. Fill the bottom of the saucepan with a little bit of water and place the bowl with the chocolate on top of it, making sure the bottom of the bowl does not touch the water. Turn on medium heat to bring the water to a simmer. Leave the chocolate to melt, occasionally stirring, until completely smooth.
The mixture might look like splitting at first but should come together unto a shiny and smooth mixture. Make sure the eggs are at room temperature. If you were to add very cold egg yolks to the chocolate, it could make it seize and split.
This step allows to lighten the chocolate mixture and will make it easier to incorporate the rest of the whipped egg whites without breaking them.