Preheat oven to 180 C / Gas 4. Grease two 23cm sandwich tins.
Sift flour, baking powder, salt, bicarb and 300g caster sugar together in a large mixing bowl. Add 100g butter and 300ml evaporated milk. Beat at medium speed with an electric mixer for 2 minutes. Beat in the eggs and beat for 2 minutes longer. Spread the mixture evenly into the prepared tins. Drizzle 60g of the melted chocolate in a spiral on top of each cake. Feather lines with a knife to form a web pattern.
Bake for 30 to 40 minutes or until a skewer inserted in the centre comes out clean. Let cakes cool in tins for 10 minutes then remove from tins and let cakes cool completely.
To make filling: Combine the 60g melted chocolate, 275g butter, 275g caster sugar, 175ml evaporated milk and the vanilla together and beat with an electric mixer until smooth.
To assemble cake: Cut each cooled cake layer in half horizontally. Spread 1/4 of the filling between each layer making a 4 layer cake with a web design on top. Ice cake with the remaining filling.
The picture doesn't appear to be the same cake or has been iced using a different recipe, see picture 2 for what it looks like when it comes out of the oven. The chocolate sunk to the bottom of the tin as I suspected it would. If photo 1 is the same cake then they may have used different icing as there is nothing listed to make the white lines and even when I added more chocolate to the icing to make it darker it still came out a toffee/coffee colour. Although it looks ok its not as dark as the 1st picture so not as striking. However I would say that I ate a few crumbs that fell off and it tasted really nice so hoping its yummy. Don't know if you can see my profile photo but the cake is under the spiders, you can see the colour when I made it! Happy Halloween!
Have eaten some now, its lovely but very rich, bit too much icing and not enough sponge? - 29 Oct 2010