- 1/2 lb / 225g butter
- 2 1/3 cups / 1 pound / 450g / caster or granulated sugar (superfine works best if you have it handy)
- 4 eggs
- 9 rounded tablespoons grated chocolate (approximately 3 standard squares of baking chocolate, or 90 grams / 3 1/2 ounces of other chocolate)
- 5 rounded tablespoons / 50g / 1 3/4 ounces ground almonds
- 3 tablespoons cocoa
- 1 cup / 5 ounces / 150g of cold, sieved or riced cooked potato (see below for specific directions about the potato)
- 2 1/2 cups / 10 ounces / 300g flour (plain flour is fine, but cake flour is better if you have it)
- 1/2 teaspoon cinnamon
- 2 rounded teaspoons baking powder
- 1/2 teaspoon salt
- 2/3 cup / 5 fluid ounces / UK 1/4 pint / 150ml milk
For preparing the pan you’ll bake in:
- 1 1/2 tablespoons flour
- 1 1/2 tablespoons cocoa
First prepare your cake pan. A tube pan like a Bundt pan works best for this recipe: but a springform cake pan works fine too.
- If using a tube pan or Bundt pan, butter it well inside, paying particular attention to any flutings or crevices in the pan. Then mix the flour and cocoa together and use this mixture to flour the inside of the pan.
- If using a springform pan, butter it too: then line it with a circle of buttered baking parchment for the bottom and a strip of buttered baking parchment for the sides.
Now prepare your cooked potato by one of these two methods:
- Boil in unsalted water 2 medium-sized potatoes or 3 small potatoes in their jackets, then drain, cool completely, peel, and rice or sieve.
- Or if you prefer, peel and chunk 2 medium-sized potatoes or 3 small potatoes, boil for 15 minutes or until cooked through. Drain them, dry them briefly over low heat until most of the steam has stopped rising, then remove from heat and mash well, ricing or sieving when fully cooled.
- An important note about the potatoes: Do not add them to the batter if they are even slightly warm. If you do, the result will be a heavy cake that may fail to rise, or only rise partway. Also: We have never tried this cake with instant mashed potatoes. Better to play it safe and use the real thing.
- Preheat the oven to 350° F / 275° C. Then prepare the cake batter:
3. Grate the chocolate on a fine grater, or pulse in a food processor, or crush with a mortar and pestle, until reduced to small granules. (The food processor is by far the easiest and fastest way: the grater and mortar-and-pestle are more labor intensive, but produce a slightly finer result.
4.When this is done, sift the flour once by itself. Then sift it a second time with the cinnamon, baking powder and salt.
5. Cream the butter with the sugar until light and fluffy.
6. Separate the eggs. Add the yolks, one at a time, to the creamed mixture, beating well after each one.
7. Stir in the grated chocolate, ground almonds and cocoa. Add the sieved potato and stir again.
8. Add the flour alternately with the milk, beating gently until smooth after each addition.
9. When this process is complete, whip the egg whites until stiff but not dry. Fold the whipped egg whites carefully into the cake mixture.
10. Spoon into the prepared springform pan or Bundt pan / tube pan: tap gently once on the counter to settle. Bake for 1 3/4 hours. Test for doneness with a toothpick or skewer at the end of this time: bake for another 15 minutes if needed.
11. Remove from the oven and allow to rest in the pan for at least twenty minutes before removing from the pan: then cool on a rack.
12. To finish, frost the chocolate cake with a chocolate-based icing, or (if you prefer the simple approach) dust with confectioners’ sugar / icing sugar.
* For those who’re interested, Butlers Irish Chocolates are available in the US from this online source.