To caramelize the nuts
Combine the nuts and sugar in a pan, toast over a medium heat for approx. 5 mins. until golden brown, stirring constantly.
Place the chocolate in a thin-sided bowl and suspend over a gently simmering bain-marie; the bowl must not touch the water. Melt the chocolate and stir until smooth. Beat together the egg yolks and sugar using the whisk on a hand mixer for approx. 5 mins. until the mixture is light and fluffy. Add the egg mixture to the chocolate, pour in the espresso and mix well. Carefully fold the whipped cream into the mixture using the whisk. Beat the egg whites with the salt until stiff, add the sugar, briefly continue beating. Carefully fold the egg whites into the chocolate mixture. Fill the glasses with the mousse, cover and leave to set in the fridge for approx. 1 hr.
Whip the cream until light and fluffy, top the mousse with the cream and nuts.