Ingredients

2 large eggs

1/4 cup sugar

3 ounces semisweet chocolate, finely chopped (2/3 cup)

1 tablespoon Dutch-process cocoa powder

2 teaspoons instant espresso powder

1/4 teaspoon kosher salt

1 tablespoon unsalted butter

1/2 cup heavy cream, plus more, lightly whipped, for serving

4 Belgian spice cookies, such as Lotus Biscoff, lightly crushed, plus more for serving

Preparation

Whisk together eggs and sugar in a heatproof bowl set over (but not in) a pot of simmering water until doubled in volume and a thermometer registers 160 degrees (6 to 8 minutes). Remove from heat. Add chocolate, cocoa, espresso powder, and salt. Stir in butter until melted. Let cool slightly.

Meanwhile, whip cream to stiff peaks. Stir one-third of whipped cream into chocolate mixture until lightened, then fold in remaining whipped cream. Divide half of mousse between two glasses; sprinkle with crushed cookies. Top with remaining mousse and refrigerate until set, at least 1 hour and up to 1 day. To serve, top with lightly whipped cream and more cookie crumbs.