<human>: Can you tell me how to make a delicious chocolate mousse?
<bot>: To make a delicious chocolate mousse, start by melting some dark chocolate in a bowl set over a pan of barely simmering water. Once the chocolate has melted, remove from heat and stir in 1/2 cup of whipping cream. Let it cool for 5 minutes before adding 3 tablespoons of butter. In a separate bowl, whip together 4 egg yolks, 1/4 cup of sugar, 1 teaspoon of vanilla extract and 2 tablespoons of cocoa powder until light and fluffy. Fold the whipped eggs into the cooled chocolate mixture. Finally, fold in 1 cup of heavy cream. Spoon the mousse into individual serving dishes and chill for at least 4 hours before serving. Enjoy!