Need I say any more? All you need is a spoon!
3/4 cup chilled heavy cream
4 large egg yolks
1/4 cup espresso or strong coffee at room temperature
3 tbsp sugar, divided
1/8 tsp kosher salt
6 oz semi sweet chocolate (60% – 72% cacao) chopped
Beat 1/2 the cream in a medium bowl until stiff peaks form; cover and chill.
Combine the egg yolks, espresso, salt and 2 tbsp sugar in a large metal bowl.
Set over a saucepan of gently simmering water (do not allow the bowl to touch the water).
Cook, whisking constantly, until the mixture is lighter in color and almost doubled in volume and an instant read thermometer inserted into the mixture registers 160 degrees, about 1 minute.
Remove the bowl from the pan. Add the chocolate; whisk until melted and smooth. Let stand, whisking occasionally, until room temperature.
Using an electric mixer, beat the egg white in another medium bowl on medium speed until foamy. With the mixer running, gradually beat in the remaining 1 tbsp sugar. Increase the speed to high and beat until firm peaks form.
Fold the egg whites into the chocolate in 2 additions; fold the whipped cream into the mixture just enough to blend.
Divide the mousse among 6 teacups or 4 oz ramekins. Chill until firm, at least 3 hours.
Do ahead- The mousse can be made 1 day ahead; cover and keep chilled. Let stand at room temperature for 10 minutes before serving.
Before serving, whisk the remaining 1/4 cup cream in a small bowl until soft peaks form and dollop over the mousse