Place the sugar in a heavy-based frying pan over a medium heat and stir occasionally until the sugar has dissolved. Continue to cook until the caramel turns a golden amber colour. Remove from the heat and pour onto a silicone matt or a parchment-lined baking tray. Using a spatula, smooth out into a thin layer and leave to cool. 

Line two baking trays with parchment paper and set aside.

To brown the butter, add half the butter to a medium saucepan over a low heat. Swirl the butter in the pan occasionally. It will foam, and start to crackle and pop. Once it turns a hazelnut brown and you notice a nutty scent, it’s ready. Immediately pour the butter into a small bowl, bits and all, and allow it to cool to room temperature.

Beat the remaining butter with the brown sugar for 3-5 minutes until the mixture is smooth. Beat in the Dr. Oetker Madagascan Vanilla Natural Extract and golden syrup. Add the cooled brown butter into the bowl, along with the granulated sugar. Beat for two minutes, until light and fluffy. Add the egg and egg yolk and beat again.

Add the flour, salt, and bicarbonate of soda, beating on low speed just until everything is incorporated. 

Once the caramel has cooled and hardened, gently peel away from the silicon matt or parchment paper and transfer to a chopping board. Chop into small pieces. Use a spatula to fold in the caramel pieces and the Dr. Oetker Dark Chocolate Chunks and finish incorporating all of the dry ingredients into the dough.

Scoop the dough onto a piece of parchment paper or cling film. Flatten it slightly into a thick disk and refrigerate for at least 30 minutes.

About 15 minutes before you’re ready to begin baking, place racks in the centre and upper third of the oven and preheat your oven to 175°C/160°C fan/gas mark 4.

Shape the dough into tablespoon-sized balls, and place onto the prepared baking trays, leaving about two inches between the cookies. Sprinkle the cookies with sea salt, and bake for 10-13 minutes, until golden brown. Remove from the oven and allow to rest for at least five minutes before moving them.