Preheat oven to 180 degrees celsius (fan-forced). Line a 20 X 20cm cake tin with baking paper or foil, leaving an overhang on two sides.
Melt the butter in the microwave. Add the brown sugar and vanilla and whisk together until the sugar has dissolved.
Add the plain flour, oats, bi-carb and salt. Stir until combined.
Add half of the mixture to the tin and press down firmly.
Bake in the oven for 10 minutes.
Meanwhile combine the caramels, cream and salt in a saucepan (or in the microwave) over low heat. Stir until melted and well combined (about 5 minutes).
Spread the chocolate chips over the cooked oat base.
Pour the salted caramel sauce over the top of the chocolate chips.
Crumble the remaining oat mixture over the top.
Cook for approximately 15 minutes in the oven.
The slice will be ready when the oats have turned golden and the caramel sauce in the middle is bubbling.
Allow the slice to cool in the tin and then place in the fridge overnight.
Take the slice out of the fridge and cut into squares.