Two desserts in one – just the way we like things at The Great British Bake Off. The mousse is very rich, so serve it in small portions, or even use it as a dip for the churros.
Make the mousse. Place the double cream in a small bowl and, using an electric hand whisk, whip the cream to soft peaks.
Place the egg yolks in the bowl of a stand mixer fitted with a whisk attachment. Mix on a low–medium speed until pale.
Place the sugar in a small pan with 1 tablespoon of water. Cook over a low heat until the sugar dissolves, then increase the heat and cook until it reaches 120°C/248°F on a sugar thermometer. Remove from the heat.
Turn the mixer speed up to medium and pour the sugar syrup into the egg yolks in a thin, steady stream. Increase the speed to high and whisk until the mixture is pale, fluffy and cool to the touch.
Melt the chocolate in a medium bowl over a pan of gently simmering water. Once melted, remove from the heat, stir until smooth and leave to cool slightly. Fold a heaped tablespoon of the whipped cream and all the orange liqueur into the chocolate, then fold the chocolate mixture into the egg yolk mixture with the remaining cream, trying to keep as much air in the mousse as possible. Spoon equally into 6 serving glasses, cover and chill for about 1 hour to set.
Once the mousses are set, make the topping. Whip the double cream and caster sugar together until the mixture holds soft peaks, then place the sweetened cream in the medium piping bag fitted with a large star nozzle. Pipe the cream on top of the mousse and sprinkle with grated milk chocolate to finish. Chill until ready to serve.
Make the coulis. Blitz the raspberries in a food processor, then sieve the pulp to remove the pips and leave a smooth purée. Stir in the icing sugar, to taste. Chill until ready to serve.
Make the churros. Place 240ml of water, the sugar and the butter in a medium pan over a medium heat and heat until the butter has melted. Bring the mixture to the boil, then immediately remove the pan from the heat and add the vanilla and salt and tip in all the flour. Beat with a wooden spoon until the mixture forms a smooth paste that cleanly leaves the sides of the pan. Allow to cool for 5 minutes, then using an electric hand whisk, gradually whisk in the eggs until you have a smooth, thick paste. Spoon the mixture into the large piping bag fitted with the fine-toothed nozzle.
Heat the oil in a deep-fat fryer (or large, deep pan) until it reaches at 190°C/374°F on the thermometer. In batches, pipe the churro dough into the hot fat, making each churro about 10cm long (cut each length off with scissors or a knife). Fry for 3–5 minutes per batch, turning the churros as they cook, until golden brown all over. Remove with a slotted spoon, then set aside to drain on kitchen paper while you fry the next batch. Roll the warm churros in the caster sugar and cinnamon mixture to coat. Serve with the coulis for dipping, and the mousses alongside.