Mocha Mousse with Sichuan Peppercorns (Mousse au Moka et Poivre)

From Epicurious.
Ingredients:
1/4 tsp. Sichuan peppercorns, ground
1/3 c. heavy cream
1 1/2 tsp. ground coffee beans
4 oz. 70% cacao bittersweet chocolate, chopped
3 large egg whites
1 Tbsp. sugar

Bring cream, coffee, and pepper to a simmer in a small saucepan. Remove from heat and let steep, covered, 30 minutes. Strain cream through a fine-mesh sieve into a bowl, pressing on solids.
Melt chocolate in a large bowl. Stir in cream. Cool slightly.
Beat egg whites with sugar using an electric mixer until they just hold stiff peaks. Fold into chocolate mixture gently but thoroughly.
Spoon mousse into glasses and chill at least 3 hours.
Serves 4.