In a small saucepan, add half the heavy cream and heat on low until it begins to simmer. Remove from heat.

Place chopped chocolate in a heatproof bowl and pour warm cream over it. Add vanilla extract.

Let the mixture sit for a minute, then whisk until smooth and fully combined.

Whisk in the remaining cold heavy cream to cool down the mixture.

Cover and refrigerate for at least 2 hours until chilled.

Once chilled, whip the chocolate cream with an electric mixer until stiff peaks form, being careful not to overmix.

Distribute the mousse into serving bowls and top with whipped cream, if desired. Serve immediately.