The original Diversnight cake by Tone Svee Dahl (the founder of Diversnight).

Cake base:
6 eggs.
4 cups sugar (one cup roughly 2dl).
6 cups all-purpose flour.
6 tsp baking powder.
6 tsp vanilla sugar.
450 grams melted butter.
3 cups milk.
4 tbs cocoa powder.
 
Preheat the oven to 190 degrees celcius or 374 degrees Fahrenheit (gas mark 5).
Mix eggs and sugar fluffy.
Add the rest of the ingredients one by one while mixing.
Pour mixture into a greased deep baking/roasting pan.
Place the pan in the middle of the oven.
Cook for 30-40 minutes.
Leave the cake to cool off while making one of the frostings below. When the cake is cool, spread the frosting over it and decorate to your liking.
Bring the cake to the dive site, have a fantastic dive and share the cake.
 
Frosting #1:
200 grams butter.
500 icing sugar.
4 tsp sugar.
6 tbs coffee (espresso is great to use here!).
3 tbs cocoa powder.
 
Melt the butter, add in the rest of the ingredients and mix until smooth and lump-free.
In case of too runny, add more icing sugar.
 
Frosting #2:
200 grams white chocolate.
90 grams butter.
300 grams icing sugar.
5-7 tbs boling water
3 tbs cocoa powder.
 
Consider doubling the recipe, as there can never be too much frosting on a Diversnight cake!
Melt the butter with the boiling water in a casserole.
Add the chocolate and let it melt over low heat, do not allow to boil!
Mix in the icing sugar and stir until smooth and lump-free.
In case of too runny, add more icing sugar.