1. Melt the butter and chocolate in a bain-marie until smooth.
2. In a separate bowl, beat the eggs with the sugar for about 3 minutes until the mixture turns white and frothy, then add the melted chocolate.
3. Mix the flour with the baking powder and salt, sift, and add to the egg and chocolate mixture. Mix thoroughly.
4. Gradually pour in the dark beer, stirring constantly, until the mixture is smooth.
5. Preheat the oven to 180 degrees. Pour the mixture into a baking tin lined with baking paper and bake for 30–35 minutes.
Enjoy!