Ingredients 200g dark chocolate, broken into pieces 150g unsalted butter, plus extra for greasing 250g caster sugar 3 large eggs 1 tsp vanilla extract 100g plain flour 30g cocoa powder Pinch of salt Optional Add-Ins 100g chopped nuts (e.g., walnuts or pecans) 100g chocolate chunks or chips A handful of mini marshmallows Method Preheat the oven: Set your oven to 180°C (160°C fan) or Gas Mark 4. Grease a 20cm square baking tin and line it with baking parchment. Melt the chocolate and butter: Place the dark chocolate and butter in a heatproof bowl over a pan of simmering water (don’t let the bowl touch the water). Stir until melted and smooth. Alternatively, microwave in short bursts, stirring in between. Set…