Gather all of your ingredients and preheat your oven to 180C. Using a pan, melt your margarine on a medium heat, alongside the sugar, cocoa and water. Keep on a medium heat until you have a smooth mixture. Now remove from heat and stir until it's cooled down.
Grab a bowl and sift the flour and baking powder. Using a separate bowl, separate the whites and the yolks in the eggs from one another. Now whisk the egg whites until stiff peaks form. With the egg yolks, add them individually to the cooled margarine mix and incorporate well. Once the yolks are mixed in, add the stiff egg whites gently. Mix well.
Grease two circular cake tins, and line with parchment paper. Divide the batter equally between the prepared pans and bake for around 25 minutes in the center of the oven. You can check whether the cake is done by inserting a toothpick into the center - if it comes out clean, your cake is ready. Remove from oven and leave to cool on a wire rack.
Add the whipped cream to a bowl and mix well until it becomes firm. At this point, add the icing sugar and continue whisking for a minute or so. Set aside. Add all of the punch ingredients to a glass and stir well. Set aside.
Once cakes are cooled, level the cakes using a knife. Place one of the cakes onto a serving plate and soak with half of the prepared punch. Now using a knife or spatula, spread the jam. On top of the jam, use around 3/4 of the cream mixture and add the second layer of cake on top. Use the remaining punch to soak the second cake.
Use a pan to heat the double cream. Remove from heat once warm and add the chocolate and vanilla. Wait until it's melted and mix until it's smooth. Now spread the icing over the top of the cake, and decorate the sides of the cake with the remainder of the whipped cream. Use strawberries for garnish on the cake.