1. Grease 3 x 7″ round sandwich tins (or 2 x 8″).
2. Preheat the oven to 180C.
3. Cream your room temperature butter with your sugars until it’s pale, light and fluffy.
4. Mix in the eggs, one at a time, beating really well after each egg. Don’t worry if it starts to look a bit curdled, it’ll all come good.
5. Mix in your flour and cocoa. If you’ve been using a mixer, do this bit by hand. It helps to keep the sponge light.
6. Spoon into a your tins, smooth out with the back of a spoon. Make a bit of a dip in the middle to account for rising.
7. Bake for about 30 minutes or until a skewer comes out clean. You might need to adjust the time by 5 minutes either way depending on your oven.

Make your icing:

1. Melt the chocolate in a bowl set over a pan of boiling water. Remove from the heat and allow to cool.
2. Meanwhile, beat your butter until it is pale, light and fluffy.
3. Add the icing sugar to the butter and beat again until it's all combined (it'll be very stiff).
4. When the chocolate has cooled for at least 10 minutes, add it to the icings and beat until smooth (is that the most beautiful sight you've ever seen?)

Putting it together:

1. When your cakes are completely cold, use a carving knife to level them. Just trim the top crust off. This is important, it’s not a waste of cake (taste testing compulsory). If you don’t do this, with a cake this size it will be wonky.
2. Open the can of caramel and scoop into a bowl. Give it a stir to smooth the consistency.
3. Use about a third of the tin to sandwich the first two layers together and a further third of the tin to add the third layer on top. Reserve the rest of the caramel.
4. Cover the top and sides of the cake with the buttercream icing and smooth.
5. Pile your marshmallows and chocolate goodies on top of the cake.
6. Drizzle with the remaining caramel.
7. Enjoy admiring glances!