1. Rub the margarine, sugar and gluten free plain flour together with your fingers until you get a breadcrumb consistency then bring together to form a dough ball.

2. Wrap the dough in cling film and chill for 20-30 mins to firm up.

3. Roll out the dough until just thicker than a pound coin and cut to size (go roughly to the size of your silicone moulds, cut just slightly smaller than your cut outs).

4. Place your shortbread fingers onto a baking tray, they are ok to be fairly close, they don't spread much. If you are making the smaller Twix biscuits, bake on gas 3/160c for 15 mins, for the larger ones, they will need around 20-25 mins.

5. Remove from the oven and allow to firm up for 10 mins before taking off the tray. Let them cool fully.

6. Break the chocolate into a bowl and melt in a microwave in 30 second bursts, spoon into silicone moulds lining the bottom and sides, then shake out excess back into the bowl to leave a thinner coating in the moulds. Place in freezer for 10-15 mins to firm up. Larger one may need a little longer. If you don't have freezer room you can place in the fridge for an hour or so until solid to the touch.

7. Warm the caramel (shop bought or if you are making your own see the caramel steps in my chocolate and salted caramel trifle recipe. I would suggest making this ahead of making the Twix bars so it is ready and cool) to loosen up for 10 secs. Spoon the caramel into the chocolate casings (around 1tsp in each small and 3 quarters tbsp in the large).

8. Press your shortbread fingers on top of the caramel then top with more melted chocolate. Gently shake to get out air bubbles and help the chocolate fully cover and go down any gaps. Put in freezer for a further 30-40 mins to set (or fridge for 3-4 hours).

NB: The moulds are used were these:-
Small finger moulds
Large finger/lady finger moulds

Any caramel sauce would work for this but a more solid spread works best such as this one

Nutritional info given in the table is for small bars, here are the nutritional values for the large (recipe makes 8 or 9 large bars compared to 20 small)
Calories - 346g
Carbs - 40g
Fat - 20g
Protein - 3g
Fibre - 0g
Sugar - 32g