Preheat the oven to 350 F. Grease a 9” springform pan and set aside.

In a medium microwave safe bowl, melt together the chocolate and butter in 30 second increments, stirring after each, until smooth.

Stir in the sugar, followed by the eggs, one at a time. Mix in the vanilla.

Stir in the cocoa powder until fully combined, then transfer to the prepared pan.

Bake in the preheated oven for 10-15 minutes, or until the brownie has formed a crust.

Allow to cool.

Melt the chocolate in 30 second intervals in the microwave, stirring after each, until the chocolate is melted and smooth; set aside to cool

In a large bowl, cream together the cream cheese and sugar until smooth. Add the eggs and vanilla, one at a time, scraping down the bowl and mixing well in between each addition.

Add the sour cream and stir to combine. Add the cocoa powder and mix well. Mix in the melted chocolate and stir until the batter is a uniform brown color.

Pour the batter into the pan with the brownie crust, then return to the oven and bake for 50 - 65 minutes, or until the edges are set and the center wobbles slightly.

Allow to cool for 1 hour in the oven with the door open, then remove from the oven and allow to cool completely. Transfer to the fridge to chill for at least 6 hours or overnight.

In a medium pan over low heat, melt the chocolate and butter until smooth, allow to cool slightly, then add the egg yolks and whisk until smooth.

In a separate bowl, whip the egg whites until foamy, then add the cream of tartar and whip until stiff peaks form. Fold into the melted chocolate mixture.

Spread the mousse evenly over top of the cheesecake with the sides still on the pan. Allow to chill for at least 2 hours to set.

Remove the sides of the pan and garnish each slice with whipped cream and a piece of godiva dark chocolate.