Salted caramel chocolate mousse

Divide the caramel between 6 x 175ml ramekins or glasses. Place a heatproof bowl over a pan of barely simmering water (making sure it doesn’t touch the water) and add the butter. Break the chocolate into small pieces and add it to the bowl, stirring occasionally, until melted. Lift the bowl from the pan, stir in 1 tbsp just-boiled water and set aside.

Put the egg yolks and 1 tbsp sugar in a large, clean bowl and place over the pan of barely simmering water. Using an electric hand mixer, whisk for 3-4 minutes, until pale and thickened. Take off the heat and stir the chocolate mixture through the egg yolk mixture.

Put the egg whites in a clean bowl with the salt and lemon juice. Clean the beaters, then whisk to stiff peaks. Whisk in the remaining 2 tbsp sugar, until firm and glossy.

Stir ⅓ of the beaten egg white through the chocolate mixture to loosen, then carefully fold in the rest, retaining as much air as possible. Spoon the mousse into the ramekins or glasses and chill for at least 4 hours, or up to 48 hours, until set. Sprinkle the tops with a little more flaky sea salt before serving, if liked.