1 For the caramel: Make the caramel by placing the sugar and water in a medium saucepan, give them a mix so they are well combined, and place over a medium heat.

2 Cook until the caramel becomes a deep golden colour, swirling the pan regularly to evenly distribute the sugar and ensure it colours uniformly.

3 Once the caramel has reached a dark golden brown, add the butter and whisk to combine, taking care as the caramel will spit a little.

4 Slowly pour in the cream, whisking all the time, keeping the caramel on a low heat.

5 Bring the caramel sauce back up to the boil, continuing to whisk all the time. Add the vanilla and salt.

6 Remove the caramel from the heat and leave to cool completely. Once cool the caramel can be stored either in the fridge or in an airtight container at room temperature.

7 For the cookies: Cream the butter until pale and soft, using an electric beater, stand mixer, or by hand. Add the 225g caramel sauce (reserving any remaining caramel to drizzle over the cookies once baked, or for another use), and cream together until well combined.

8 Add the egg, mix well, then sift in the flour, bicarbonate of soda and the baking powder. Beat the dry ingredients into the mix, followed by the dark chocolate, until just combined.

9 Chill the dough in clingfilm or place in a container for about 30 minutes.

10 Meanwhile, preheat the oven to 190 degrees or 170 degrees fan. Line two baking trays with parchment paper, and divide the cookie dough into 12 balls (about 40g each if you're being exact).

11 Place the cookie balls on the baking sheets, a few centimetres apart, to allow the cookies to spread out. Bake for 15 minutes, then remove from the oven. Sprinkle the cookies with a little sea salt while warm. Leave to cool slightly, the cookies will continue to cook a little on the tray.