Fill a large bowl with ice water. Place a medium bowl that fits just into the large bowl into the ice water bath. Set aside.

In a medium saucepan over medium heat, melt the dark chocolate, peppermint extract and water, stirring occasionally until melted completely.

Pour the melted chocolate mixture into the medium bowl resting in the ice bath. Whisk the chocolate mixture until it becomes thick, taking care not to over mix as it’ll become too stiff and grainy. You’ll feel the resistance as soon as it becomes thick; stop there.

Transfer the mousse into 4 small bowls. Serve immediately or chill in the refrigerator until ready to serve.