Method (shortbread base)

1. Preheat oven to 180°C fan, and line a square baking tin with greaseproof paper. Make sure the base and sides are fully lined, as the caramel could stick.
2. In a medium mixing bowl, sift in the flour and sugar. Add in the butter and vanilla extract, using your fingertips, rub the butter into the dry mixture until a dough forms. Form into a ball.
3. Press the dough into the lined tin, making sure it’s even. Prick the base with a fork.
4. Pop into the oven and bake for 30 minutes or until lightly golden in colour. Once golden, remove from the oven and place the tin onto a cooling rack.
5. Leave the shortbread in the tin as we’ll be pouring over the caramel.

Method (caramel)

1. Add all of the caramel ingredients into a medium-sized saucepan. Place on the hob, heat the caramel on low / medium, stirring all the time until it turns a amber colour. This will take approximately 15-20 minutes. You want the caramel to reach firm ball stage (if you drop a little caramel into ice-cold water it should form a firm non-sticky ball in your fingers). If the caramel hasn’t reached this stage, cook it for a little longer.
2. Once ready, carefully pour the caramel over the biscuit base, leveling off with a spoon. Be very quick as this caramel sets quite quickly.
3. Refrigerate for 3-4 hours or until the caramel is set and firm.  for an hour before coating. Make sure the caramel has fully set, if not, it will be very gooey and a nightmare to coat in chocolate.

Method (chocolate)

1. Fill a small saucepan 3/4 full with water, creating a bain-marie, place onto the hob over low/ medium heat.
2. Finely chop the dark chocolate and place into a heat proof bowl. Place the bowl on top of the saucepan and allow to melt. 
3. Cut the bars into thin, finger-width sizes. Tip: To get an even amount of bars, slice the entire sheet in half (width-wise), then cut about 6 bars from each half, for a total of approximately 12, thin bars. Use a large, sharp knife to prevent the biscuit base from crumbling apart. 
4. One by one, balance the Twix Bars on a fork or spatula, and using a spoon, pour the chocolate over the bars, allowing any excess chocolate to drip back into the bowl. Don’t try to dunk the bars as that risks the shortbread base from crumbling. Repeat for all bars. Place them onto grease proof paper and pop into the freezer for 10 minutes or fridge for 30 minutes to allow the chocolate to set.
5. Drizzle any left over chocolate for decoration.
6. Serve with a sprinkling of sea salt (optional).