Preheat your oven to 350°F (175°C). Whisk the eggs and 1/2 cup of sugar together for about 10 minutes until pale and fluffy. Fold in 1/2 cup of flour until just combined, pour into a greased 9-inch cake pan and bake for 25-30 minutes.

While the cake cools, prepare a soaking liquid by combining 1/2 cup of boiling milk with a bit of sugar if desired. Soak each layer evenly with the milk mixture.

Beat together 2 pounds of sour cream and 1 1/2 cups of sugar until fluffy. Add 15 ounces of sweetened condensed milk, combine, then heat 1/2 cup of milk with 4 packets of Knox gelatine until boiling and whisk into the sour cream mixture.

Divide the mousse filling between two springform pans, smooth tops, cover with plastic wrap and refrigerate for approximately 3 to 4 hours until set.

Heat 1 cup of heavy cream until boiling. Pour over 1 cup of chocolate chips, let sit for a minute, then whisk until smooth. Allow ganache to cool slightly.

Remove mousse layers from pans. Place one layer on a serving platter, top with half of the ganache, add second layer, pour remaining ganache over and smooth out. Refrigerate for another 30 minutes before serving.