After some research, I found this tutorial for a Portal Cake by The Geeky Chef: http://www.geekychef.com/2010/09/delicious-and-moist-cake.html
As the recipe used US measurements and ingredients, one of the most time-consuming parts of the project was converting it into grams and finding UK versions of the ingredients featured, so I've put this tutorial together using ingredients that you can get from most UK supermarkets.
Although the cake itself is pretty ambitious this tutorial is suitable for complete newbies - I haven't baked in about 8 years and was figuring out most of the techniques used in the recipe from scratch, and have included tips on anything that went wrong.
A couple words of warning: this cake isn't exactly cheap - the cherry liquor alone was £8 and the recipe uses most of the bottle. You'll also need two free evenings (or an entire day) to complete it: one for the baking and one for decorating it after it cools.
Also, after baking one as a trial run I couldn't be bothered doing it all again for the actual bake off. I'll be posting another Instructable soon of the next cake I tried: a peach pie with laser cut icing.
Step 1: What You'll Need
- 213g Plain Flour
- 85g Unsweetened Cocoa Powder (eg Bourneville, Green & Black's or anything made from 100% cocoa)
- 1 and a half teaspoons Baking Powder
- 1 teaspoon Salt
- 104g Vegetable Fat (eg Trex)
- 300g Granulated Sugar
- 2 Eggs
- 1 teaspoon Vanilla Extract
- 242g Buttermilk
Ingredients for the filling, topping and icing:
- 190ml Kirsch
- 2 tins Black Cherries
- 1.2 litres Double Cream
- 32g Icing Sugar
- 3 tablespoons of the Unsweetened Cocoa Powder
- 1 bar Plain Cooking Chocolate (70% cocoa or above)
- 8 Maraschino Cherries
- Two 8-inch cake tins
- Greaseproof Paper
- Two large mixing bowls or saucepans
- Electric whisk
- Cheese grater
Some tips on ingredients and supplies:
Most of the ingredients are available at Asda: I tried to use the cheapest ingredients possible so Asda's own products are absolutely fine. I had some trouble finding maraschino cherries and eventually found them in the Polish food section. Vegetable fat was in the butter aisle, and the plain chocolate and vanilla extract were in the baking aisle.
The two ingredients they didn't stock were Kirsch and tinned black cherries. I eventually found these in Waitrose after trawling through a few different supermarkets.
Lastly, for the love of God get an electric whisk! Don't let anyone on the internet tell you that you can whip cream by hand: anyone who's actually tried it will tell you to give it up and go buy an electric whisk.
Step 2: Preheat the oven and prepare the cake tins
Step 3: Prepare the cake mix
In the other mixing bowl, beat the vegetable fat and granulated sugar together. Start off by breaking up the vegetable fat with a wooden spoon, then use a fork to beat the mixture until it has the appearance and consistency of scrambled eggs (see pic 3).
Add the eggs and continue beating the mixture with a fork until it looks recognisably like cake mix (see pic 4).
Mix in the vanilla extract.
Finally, add the flour mixture and buttermilk, alternating between them and gradually mixing them in a bit at a time.
Step 4: Bake it and add the Kirsch
Leave them to cool for a few hours or overnight. When completely cooled, cut them in half horizontally to make four layers, and sprinkle 125ml of Kirsch over them.
At this point it'll be pretty soggy, and the final cake will be *really* strong. It'll taste awesome though.
Step 5: Prepare the filling and icing
To make the icing, whip the double cream and the icing sugar together with an electric whisk until it forms peaks that can stand up on their own (see pic 2). You'll need *a lot* of icing to fill and cover the entire cake.
Put aside 4 tablespoons of the icing to use for topping the cake.
Mix 3 tablespoons of the cocoa powder into the rest of the icing.
Step 6: Add the filling
This is where it starts to get fiddly. Add the second layer of sponge and add more of the icing and cherries on top. Repeat for the third layer, using the last of the cherries, then lay the fourth layer of sponge on top.
After the first layer it got really difficult to keep the whole thing intact and I had to stop taking photos so I could hold it together with one hand while ladelling on icing glue with the other. It would probably have helped to chop up the tinned cherries before using them in the filling, as the whole cherries were raising the cake up in the middle and making it sag at the edges.
If your cake is anything like mine it'll look a bit of a mess at the moment, but we'll sort that out in the next step.
Step 7: Add the frosting
Tidy the icing up a bit with a knife or spatula and it should be looking half-decent.
Step 8: Add the chocolate topping
This will make a right mess and you'll probably need a compliant housemate around to help tidy it up a bit afterwards.