To make the cake:

1. Preheat oven to 350 degrees F (176 C).
2. In a large mixing bowl whisk together pumpkin puree, coconut sugar, eggs, butter, maple syrup, vanilla extract, and apple cider vinegar until well combined.
3. In a separate mixing bowl, combine almond flour, tapioca flour, coconut flour, pumpkin pie spice, baking soda, and sea salt. Stir the dry mixture into the wet, until fully combined. The mixture will be quite thick.
4. Prepare your bundt pan. Grease the bundt pan with a generous layer of softened butter (alternatively you may use softened ghee or coconut oil) with a basting brush, making sure to butter the inner stem and over the top edge of the pan in case the cake bakes over the edge when rising. After greasing the pan, coat with coconut sugar, tilting the pan until you have dispersed the coconut sugar evenly across the surface.
5. Spoon the cake batter to the bundt pan, then gently tamp down to make sure that it is fully dispersed in all of the crevices of the bundt shape.
6. Transfer the cake to the oven and bake for 40-45 minutes. You can tell the cake is ready when the surface is springy. When in doubt, you can take the internal temperature with an instant-read thermometer. The temperature in the middle should reach between 200-210 degrees F.
7. Cool the cake in its pan for atleast 20 minutes before turning it out onto a cooling rack.

To make the sauce:

1. In a small saucepan over medium heat, simmer bourbon until reduced by half.
2. Add coconut sugar, coconut milk, butter, and maple syrup and stir to combine. Allow to come to a low rolling boil and allow to thicken, stirring occasionally. Allow to simmer for 10-15 minutes or until the mixture has reached 140 degrees F.
3. Remove from heat and stir in vanilla and sea salt.
4. Drizzle over the cake before serving. This sauce is delicious cooled to room temperature or served warm. Optionally, this cake is also lovely served with the addition of a dollop of whipped cream or whipped coconut cream on top.
5. Store leftovers in an airtight container in the fridge for up to 4 days.