• Line a large baking tray with greaseproof paper. Make the pretzel brittle: add the sugar, butter and 1 tbsp water to a medium saucepan and place on a medium heat. Do not stir, but tilt the pan to ensure the heat is distributed.
• Once the butter has melted, add the golden syrup. Bring the mixture to the boil and stir to combine. Keep on a medium/high heat until it passes the sugar drop test (this will take a few minutes, but not long): get a glass of cold water and use a spoon to drop some of the sugary caramel mixture into it - if these droplets go hard upon entering the water, the mixture is ready! Add the pretzel bits, stir together and tip onto the baking tray. Set aside.

For the Brownies

• Preheat the oven to 200C/180C Fan/Gas 6. Line an 8 inch square tin. Melt the dark chocolate in the microwave in 20 second intervals. Set aside.
• In a large bowl/the bowl of a stand mixer, combine the melted butter and both sugars. Add the eggs and mix again. Slowly incorporate the melted chocolate until everything is fully combined. 
• Fold in the flour, cocoa powder, chopped milk chocolate until just combined.
• Break up the pretzel brittle into chunks - you may want to use your hands, a rolling pin or similar heavy object! Add about half to 3/4 of the brittle to the brownies - depending on how much you like! Fold together to combine.
• Pour the batter into the prepared tin. Bake for 30-35 minutes, then let cool on a wire rack before slicing and serving.