Preheat your oven to 180°C (350°F) and grease a standard muffin tin.

In a medium bowl, whisk together the plain flour, bicarbonate of soda, cornflour, and salt. In a larger bowl, cream the unsalted butter with light brown sugar and granulated sugar until light and fluffy. Add the egg and vanilla extract, then fold in the dry ingredients and milk chocolate chips.

Scoop cookie dough into prepared muffin tin and press down to create indentations.

Bake for 10-12 minutes until lightly golden brown around the edges but soft in the center. Let cool in the tin.

In a saucepan, combine granulated sugar, butter, and a splash of water; stir until sugar dissolves and turns golden. Whisk in double cream and add Yorkshire sea salt.

Spoon caramel into cooled cookie cups and let set.

Melt milk chocolate in a microwave-safe bowl. Pour over caramel in cookie cups and sprinkle with sea salt.

Allow cookie cups to cool at room temperature or refrigerate for 30 minutes to set.

Serve on a platter for sharing.