Making the Shortbread Base:

1. Use softened butter, and cream together with sugar and vanilla.
2. Add gluten free flour and coconut flour and mix until blended.
3. Line a sided pan with parchment paper, and press the shortbread dough into the bottom of the pan, in an even layer.
4. Preheat the oven to 350F, then bake shortbread for about 25 minutes, or until light golden brown. Note that gluten free shortbread browns slowly, and may need a bit longer to fully brown.
5. While baking, prepare the caramel layer. Or, let the shortbread cool and prepare the caramel later.

The Caramel layer:

1. Combine the caramel ingredients in a medium saucepan, and stir continuously over medium-low heat. Be careful not to let the sugar scorch.
2. Stir the mixture over medium-low heat until it begins to boil, continue stirring to prevent scorching and keep the mixture at a low boil for 5-8 minutes. If the boil becomes too vigorous, turn the heat down a step.
3. Take off the heat after its boiled for at least 5 minutes, and beat vigorously for 3 minutes.
4. Pour hot caramel over the cooked shortbread layer in the lined pan. The caramel will appear very liquid at this point.
5. Tuck the pan in a safe space, or back in a cool oven, and let the caramel harden and cool for approximately 2 hours. Near the end of the two hours, prepare the chocolate layer.

The chocolate layer

1. Fill a medium saucepan 1/3rd full of water, and set a glass measuring cup inside that pot to make a double boiler.
2. Break up the chocolate and place it in the glass measuring cup, add the coconut oil and monitor until the chocolate melts.
3. Stir to combine the chocolate and coconut oil. While the chocolate is liquid, pour it over the caramel layer of the millionaire shortbread bar.
4. Set the completed millionaire shortbread bars to the side, while the chocolate hardens. Refrigerate the bar for 1-2 hours to ensure the chocolate and caramel layers are hard, before cutting, if desired.

Cutting, Serving, and Storing:

After the chocolate is hardened, lift the entire ensemble out by the parchment paper lining, and place on a cutting board.

Cut into bars using a large knife. The caramel may cut easier if a hot knife is used. I found it cut fine with a cold knife, but I did initially end up with a very soft caramel layer, rather than a semi-firm one. If your caramel seems quite sticky, definitely refrigerate the bar before cutting.

Place into cookie tins or airtight containers, and refrigerate.