Grease well a 9-inch square baking dish with butter or vegetable shortening, and set it aside.
In a small bowl, place the flour, xanthan gum and salt, and whisk to combine well. Set it on the counter next to the stovetop.
Set the flavoring oil and a measuring spoon, plus the food coloring, to the side, within arm’s reach.
In a large, heavy-bottom saucepan, place the butter, sugar, corn syrup, sweetened condensed milk and Lyle’s Golden Syrup (or honey).
Cook over medium-high heat until the mixture reaches a boil, stirring constantly.
Lower the heat to medium so the mixture maintains a slow boil, and continue to cook until the temperature reaches 240°F on a candy thermometer.
Be careful to reach 240°F, the softball stage of cooking sugar, precisely. Any higher and the butter will burn. Any lower and the licorice won’t hard enough as it cools.
Remove the mixture from the heat and add the flour mixture. Working quickly, mix everything well.
Add the flavoring oil and food coloring (I generally use a toothpick to add gel food coloring), and mix well once again.
Pour the candy into the prepared baking dish, and shake it back and forth so that it is in an even layer.
Place the baking dish in the refrigerator and chill for 30 minutes.
Remove the baking dish from the refrigerator, and, with a thin spatula or other thin kitchen implement, remove the candy in one piece from the baking dish onto a flat surface.
With kitchen shears, cut the square of candy in half, and then cut each half into 1/4-inch wide strips.
Twist the strips at both ends to create the traditional licorice spiral.
Allow to sit at room temperature until slightly hardened, and serve.
Notes
I don't like using molasses in this recipe because it has a very strong taste and color, both of which I end up having to overcome with more food coloring and more flavoring oil. If you don't have/can't find/don't want to use Lyle's Golden Syrup.