<human>:  How do I make a chocolate mousse cake?
<bot>: To make a chocolate mousse cake, you will need the following ingredients: 1 box of chocolate cake mix, 3 large eggs, 1/2 cup of softened butter, 1/4 cup of milk, 1/4 teaspoon of vanilla extract, 1/4 cup of cocoa powder, 1/4 cup of brewed coffee, 1/4 cup of whipping cream, and 8 ounces of semi-sweet or dark chocolate. Preheat the oven to 350°F. Prepare the cake mix according to package directions and pour into a 9-inch cake pan. Bake for 25 minutes and let cool completely. In a medium bowl, beat together the eggs, butter, milk, and vanilla until creamy. Add in the cocoa powder and beat again. Pour the mixture into the cake pan and bake for an additional 25 minutes. Let cool. In a medium saucepan, heat the coffee and cream until warm. Add the chocolate and stir until melted and smooth. Spread over the cake. Refrigerate for 2-3 hours or until the mousse is set. Serve chilled.