Whisk together the melted butter, coconut sugar, molasses, and eggs.
Once combined, add the almond flour, tapioca flour, baking powder, spices, and salt.
Line an 8×8 square pan with parchment paper so it drapes over two sides of the pan.
Pour the cake batter into the pan and spread it out in an even layer.
Bake for 20 minutes.
Allow the cake to cool and come to room temperature before you frost it.
Make the frosting: place the cream and arrowroot in a saucepan over medium heat. Whisk continuously for about 20 seconds until the cream thickens up and pulls away from the sides of the pot as you stir.
Remove from heat and set aside to come to room temperature.
Cut the cold butter into cubes and place it in your electric standing mixer and turn it to high.
While the butter is mixing, drizzle in the agave nectar, vanilla, cinnamon, and salt.
After those ingredients are whisked together and combined, use a rubber spatula to transfer the heavy cream slurry to the mixing bowl.
Turn the mixer to high and mix until combined.
If it looks like the mixture is about to curdle – it’s ok! Stop the mixer, scrape down the sides with a rubber spatula, and continue to whip on high until it gets fluffy and creamy.
Spread the vanilla frosting out on top of the gingerbread cake. Sprinkle with additional cinnamon if desired.