Finely chop the chocolate. In a saucepan, bring the cream up to the boil, turn off the heat, add the chocolate to the cream and stir it around until the chocolate melts. Whisk in the egg yolks.
In a separate clean, dry bowl, whisk the egg whites until just stiff, then stir a quarter of the egg white into the cream mixture. Gently fold the chocolate mixture into the rest of the egg whites.
Spoon into little bowls, glasses or cups or one serving bowl and leave for an hour or two in the fridge to set.
Place the oil in a large saucepan and onto a medium-low heat. Add the popcorn kernels and swirl the pan to coat the popcorn in the oil. Put the lid on, then turn the heat down to low and listen for the popping! As soon as the popping stops, take it off the heat to avoid burning the bottom.
To make the toffee popcorn, melt the butter in a separate saucepan with the pinch of salt, add the brown sugar and golden syrup and stir over a high heat for 1-2 minutes. Pour the toffee over the popcorn, put the lid on the pan and shake to mix the toffee sauce.
Tip the toffee popcorn into a wide bowl and allow it to cool. As it cools, the toffee surrounding the popcorn will harden so every so often, break it up with your hands so it doesn’t set into one great big lump.
Dissolve the sugar in 75ml (3fl oz) water in a pan over a medium heat. Stir in the butter, raise the heat a little and bubble, stirring occasionally, until it turns a light toffee colour.
This may take about 15-20 minutes. Turn off the heat and stir in half the cream. When the bubbles die down, stir in the rest of the cream.
This can be stored in the fridge for up to 2 weeks and reheated when necessary.
To serve, drizzle the caramel sauce over the chocolate mousse, then scatter with the toffee popcorn.