For the Chocolate Cake: Heat oven to 350°F. Grease and line an 8 or 9-inch heart baking pan.

In a large mixing bowl, add the sugar, and sift in the flour, cocoa, baking powder, baking soda, mixing with the whisk attachment whisk for one minute.

Stop the mixer and add egg, sour cream, oil, and vanilla bean paste and beat on medium speed for 2 minutes.

Stir in the warm coffee and mix for 20-30 seconds or just combine with a spatula.

Pour the batter into prepared pan.

Bake 20 to 30 minutes or until wooden pick inserted in center comes out clean.

Cool 10 minutes; remove from pan to wire rack, and cool completely.

For the Chocolate Mousse: Whip the cream to soft peaks; refrigerate.

Melt the chocolate in the microwave in 20 -seconds burst, stirring between each.

Transfer the chocolate to a large bowl and let cool to 45F°.

Meanwhile, whisk the egg, egg yolks, and sugar in large bowl set over a pan of simmering water, whisk continuously until the mixture thickens (this takes around 5 minutes)

Transfer to a mixing bowl add vanilla and whisk for 7 minutes at medium/high speed.

When the chocolate is 45F° fold 1/2 of the whipped cream into the melted chocolate, fold in the egg mixture, then fold in the remain whipped cream.

Transfer to the silicone heart mold.

Place the silicone mold in the freezer, freeze overnight.

The next day, take the frozen chocolate mousse out of the silicone mold and place it on the cooled chocolate cake.

Let the mousse come to room temp before serving.