397g can caramel (stocked near the condensed milk in stores)
140g dark chocolate
140g milk chocolate
300ml double cream
Heat oven to 180C/160C fan/gas 4. Grease and line bases of 2 x 20cm sandwich tins with baking parchment. For the Vanilla & chocolate sponges, mix all the ingredients, apart from the cocoa, together with an electric whisk. Scrape half the mix into a second bowl and whizz in the cocoa. Scrape into the tins and bake for 20-25 mins until a skewer poked in comes out clean.
Repeat step 1 for the Caramel & caramel-choc sponges, again leaving cocoa out of the first mixing, then splitting the mix in half and whizzing the cocoa into one batch. Cook as above.
While sponges are cooling, melt the dark and milk chocolate together in a bowl over a pan of barely simmering water. Remove from the heat, stir in the cream and cool or chill until spreadable.
When the sponges are cool, spread a third of the caramel over the Vanilla sponge and top with the Caramel sponge. Spread over another third of the caramel and top with the Caramel-choc sponge, then the final third of caramel and top with the Chocolate sponge (don’t panic if you mix up the layers, the cake will still look great when you cut in). Spread the chocolate icing over the whole cake to serve. It will keep in a cool place in an airtight container for up to 3 days.