This rich, dark cake is the perfect way to celebrate St. Patrick's day. The heady mix of chocolate, Guinness and coffee flour create a deep, smooth sponge which is offset by the sticky sweet marshmallow frosting. It's worth noting that this is a very moist cake due to the amount of liquid ingredients used, so don't make the mistake of thinking it's underdone. When finished, the cake even looks like the famous Irish stout with a dark velvety body and creamy head. Delicious!
For One Cake
- 250ml Guinness
- 250g unsalted butter
- 75g cocoa powder
- 400g caster sugar
- 75ml sour cream
- 75ml of Strong Coffee
- 2½ tsp bicarb. of soda
- 275g plain flour
- 2 large eggs
- Pinch of salt
- Preheat the oven to gas mark 4/180°C/350ºF and butter and line a 21lb loaf tin with parchment paper.
- Pour the Guinness into a large wide saucepan with the butter and heat until melted before whisking in the cocoa powder and sugar. Beat together the sour cream, espresso and eggs and add to the pan, then whisk in the flour and bicarb.
- Pour the cake batter into the greased and lined tin and bake for 45 minutes to an hour. Leave to cool completely in the tin on a cooling rack, as it is quite a moist cake.
For the Marshmallow Icing
- (A cooking thermometer is also required for this part of the recipe)
- 4 egg whites
- Generous 1/8 tsp cream of tartar
- 150g granulated sugar
- Pinch of salt
- In the bowl of a stand mixer, stir together the egg whites, sugar, cream of tartar, and salt. Set the bowl over a saucepan of simmering water, making sure that the bowl has some clearance.
- Heat, stirring attentively and scraping down the sides of the bowl periodically with a silicone spatula, until the mixture reaches 80°C/ 175°F on a cooking thermometer (this should be about 8 minutes).
- Transfer the whites to the stand mixer with the wire whisk attached. Beat, starting slow and increasing the speed steadily, until the mixer is on full. Whip until the stiff, glossy peaks form.
- Place the frosting on top of the cooled cakes and Use a blow torch or place under the grill to caramelise.