Preheat the oven to 180 °C (350 °F). Line the bottoms of two 18-20-cm (8-inch) cake pans with circles of baking paper. Grease the pans well inside, onto the paper and on the sides.

In a medium bowl combine flour, baking powder, cocoa powder, cinnamon and salt and whisk gently.

In a large mixing bowl beat eggs with the two kinds of sugar and vanilla at high speed of the mixer for about 10 minutes. When the mixture thickens and increases its volume, add the vegetable oil. Beat until homogeneous (2-3 minutes).

Lower the speed of the mixer and add the yogurt. Mix shortly until combined. Add the dry ingredients and continue mixing until completely absorbed.

Divide the batter between the two prepared pans. Bake for 45 to 50 minutes or until a toothpick inserted in the centre comes out clean. Let the cakes cool for 10-15 minutes in the pans before removing them. They must reach room temperature before assembling the cake. Ideally refrigerate the two cakes for at least 1-2 hours before cutting them in layers.

With a rubber spatula carefully fold the chocolate mixture into the whipped cream until the mixture becomes smooth and uniform.

In a large mixing bowl beat butter and powdered sugar for 3-4 minutes, until creamy. Add cream cheese and rum extract and beat until combined. Little by little add the melted chocolate and beat until absorbed in the frosting. Beat a bit more until the frosting becomes fluffy and creamy.

Using a large serrated knife trim any uneven parts of the cakes. Cut each cake horizontally in 3 equal layers. Place one layer on a serving plate and generously spread on top Chocolate Mousse (about ⅕ of the whole quantity). Cover with another layer. Continue the process until using all 6 layers. Keep 1 tbs of the frosting for the truffles.

Spread the Chocolate Cream Cheese Buttercream Frosting on top and all around the cake.

Decorate with Chocolate truffles.

Break the trimmed parts of the cake into crumbs and combine them with 1 tbs leftover frosting. Mix well and make balls out of the mixture. Coat them with chocolate sprinkles and cocoa powder.