Steps

1. In a small saucepan, toast the Szechuan peppercorns over low heat until fragrant. Let them cool, then grind them into a fine powder.
2. Melt the dark chocolate in a heatproof bowl over a pot of simmering water, stirring until smooth. Remove from heat and stir in the ground Szechuan peppercorns.
3. In a separate bowl, whip the heavy cream until soft peaks form.
4. In another bowl, whip the egg whites with sugar and salt until stiff peaks form.
5. Gently fold the whipped cream into the chocolate mixture, then fold in the whipped egg whites.
6. Divide the mousse into serving glasses and refrigerate for at least 2 hours.
7. Serve chilled and garnish with a sprinkle of ground Szechuan peppercorns.