Grease a piece of aluminum foil. Roughly chop the almond, put it in a pan and roast it without adding any fat. Add the sugar, caramelize and pour the mixture onto the aluminum foil. Smooth out and let cool. Chop up after cooling.
For the mousse:
Roughly chop the couverture, melt in a water bath. Soak gelatin in water. Whip the cream with salt until it is semi-stiff. Save three cantuccini to garnish, coarsely chop the rest.
Whisk the egg and brandy and whip in a water bath until thick and creamy. Submit the squeezed gelatin. Add the liquid couverture, fold in the cream and add the coarsely chopped cantuccini. Also stir in half of the almond brittle.
Put the mousse in a glass bowl and chill overnight.
Just before serving, decorate with the remaining almond brittle and the three cantuccini.