The combination of shortbread cookie, creamy caramel, and chocolate is what makes TWIX bars so loveable today. This recipe takes extra measures to ensure that it replicates the timeless candy in its entirety.
Many thanks to Alexis Murphy of Jac o' lyn Murphy for helping to develop this recipe.
Preheat the oven to 300 degrees.
To make the shortbread layer, spray a 9-by-13-inch baking dish with nonstick cooking spray. In a medium-sized bowl, sift together the flour, salt, and baking powder; set aside. In a stand-mixer, beat together the butter and sugar. Add the vanilla extract and beat until combined. Slowly beat in the dry ingredients until the dough is dry and firm. Press into the baking dish and pat firmly so that the dough fills every corner. You want the dough to be about ½-inch thick. Using a fork, poke the top of the shortbread dough all over with holes. Bake in the oven for 35-40 minutes until the top is golden brown. Let cool and set aside.
For the caramel, heat the heavy cream in a medium saucepan until just simmering. Add the caramels and slowly stir until they are all melted. Season with salt and pour the caramel mixture over the shortbread, making sure to spread it around so that it coats the shortbread layer evenly. Allow the shortbread and caramel layers to cool for about 20 minutes, or until the caramel has hardened. Once cooled, cut the caramel-shortbread sticks into 8-by ½-inch sticks. Carefully remove the shortbread layers from the baking dish and lay out on a baking sheet lined with parchment paper to prepare for coating.
Using a double-boiler, melt the milk chocolate until silky and smooth. Taking each caramel-shortbread stick, dip the bottom side (the shortbread side) into the melted chocolate. Place the stick onto the baking sheet and then carefully spoon the melted milk chocolate over the top so that all sides of the caramel-shortbread stick are completely coated. Coat the rest of the caramel-shortbread sticks and let them cool in the refrigerator until the chocolate is hardened, about 30 minutes.