Makes 3x20cm (8inch) layers
200g | 7oz 70% dark chocolate, chopped
200g | 7oz unsalted butter, cubed
125ml | 4fl oz | 1/2 cup filter coffee (or water)
75ml | 5tbsp buttermilk
3 large eggs
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200g | 7oz soft light brown sugar
100g | 3.5oz caster sugar
100g | 3.5oz plain flour
100g | 3.5oz...