Preheat the oven to 180°C (350°F). Line a baking sheet with baking paper. Make sure there is enough overhang, to be able to remove from the pan easily.
Beat the softened butter with a hand/stand mixer (I used a hand mixer with a standard whisk attachment) for about 1 minute, until soft and creamy. Add flour, sugar, egg yolk, vanilla and salt. Beat on high for about 2 minutes. The mix will become a bit crumbly. Remove the mixer and with your hands make the dough come together. Press the dough into the prepared pan.
Bake in the preheated oven for about 20 minutes.
Take the pan out of the oven and allow to cool. Sprinkle with cornflakes, or crushed nuts, or pretzels. All of those are optional and the bars will be delicious either way.
While the pan is in the oven, you can prepare the caramel sauce. Allow it to cool down to room temperature, before adding to the crust. Once added to the crust, allow to cool down completely (in the fridge) before topping with melted chocolate.
In a small/medium pot heat up the chocolate with butter or coconut oil (I used butter) until melted and well combined. Can also be melted in the microwave, with a few 15 second increments. Just mix well after each one.
Pour/spread over the caramel and stick it int he fridge to cool down and to allow the chocolate to harden, before cutting.
When the chocolate has cooled and hardened, pull the bars out of the pan, using the overhang paper, careful not to crack it in the middle. Cut with a sharp knife into desired slices. Can be stored in an airtight container for up to a week. (I store it in the fridge, gives the chocolate a nice crunch).