Whisk up dairy whipping cream with an electric hand held mixer to soft peaks at medium speed (about 4 minutes) and set aside. (to test it, just the drip the cream on the surface and it should stay there for a 1-2 seconds then you have the right consistency).
In another clean bowl, whisk eggs, vanilla extract and brown sugar at high speed about 3-4 minutes at soft peaks form, no need to be very thick as double volume. To test it, you can write a letter "O" on the surface of egg batter and it should stay there for a few seconds)
Then quickly mix in the dairy whipping cream (step 1 to step 2) with a hand whisk.
Combine self-raising flour and cocoa powder together and sieve into the egg mixture in two batches. Gently fold the mixture with a rubber spatula till smooth.
Pour batter into 8 cupcake liners and some chocolate chips on top. Bake at preheated oven at 160 deg C for about 20-25 minutes or until skewer inserted comes dry.