"Chocolate Clouds" Profiterole Cake

For the sponge cake and a 26 cm in diameter springform pan:
2 eggs
200 g of sweetened condensed milk
200 g of sour cream
200 g of sugar
20 g of cocoa powder
300 g of all-purpose flour
10 g of baking powder
1/5 tsp of baking soda
For profiteroles:
50 g of butter
50 ml of water
70 ml of milk
70 g all-purpose flour
1/2 tsp of sugar
1/4 tsp of salt
2 eggs
For the chocolate cream:
200 g of chocolate
200 ml of heavy whipping cream
170 g of butter
1 tbsp of cognac (optional)
1 can (380 g) of caramelized sweetened condensed milk
For bavarian mousse:
250 ml of milk
3 egg yolks
100 g of sugar
10 g of gelatin
300 ml of heavy whipping cream
1 tsp of vanilla extract
To soak up the cake layers with:
3 tbsp of water
2 tbsp of sugar
1 tbsp of cognac
The cake is 2.7 kg