No need to heat the oven yet, this dough needs to chill. Place the butter and sugar into a large bowl, or the bowl of your stand mixer and beat on medium-high speed until light and fluffy, around 2 minutes.
Add in the egg and vanilla, scraping down the sides as necessary, and mix until well combined on medium speed, around 2 minutes.
Place the flour, salt, bicarbonate of soda, baking powder, milk chocolate chips and caramel pieces into a medium sized bowl and stir until all the chocolate chips and caramel pieces are coated in flour.
Tip the flour mix into your butter/sugar mixture and mix on low-medium speed until a soft dough forms. It should come away from the sides of the bowl and not be too sticky.
Cover the bowl loosely with cling film and place in the fridge for at least 6 hours, overnight if possible.
Once chilled, preheat the oven to 180C/350F and line two baking trays with grease proof paper/a silicone sheet.
Using a 1.5tbsp cookie scoop, place balls of dough 2 inches apart. Place in the oven for 9-11 minutes, until the edges are golden and the middle of each cookie still looks a little soft. The top of the cookies will look matte with a very slight sheen in the oven light.
Leave to cool for at least 15 minutes before digging in, if you like warm cookies, that caramel will be molten!
Once cool, store Caramel Chocolate Chip Cookies in an airtight container, at room temperature, for 5 days.