Make the cake. Preheat the oven to 350 degrees. Grease two 8-inch springform cake pans.
In a large bowl or stand mixer, combine the coconut sugar, brown rice flour, almond flour, cacao powder or cocoa powder, tapioca starch, baking soda, and sea salt.
In a separate medium bowl, whisk together the coconut milk, eggs, oil, and mint extract.
Pour the wet ingredients into the bowl with the flour mixture, and while beating on medium speed, slowly add the hot coffee or water, and continue to beat until batter is formed.
Evenly distribute the batter between the two cake pans. Bake 30-35 minutes until cakes are firm to the touch and toothpick inserted comes out clean. Allow the cakes to completely cool (about 2 hours) before frosting.
To make the frosting, combine the coconut oil and butter or palm oil shortening in a large bowl. Beat with a hand mixer or immersion blender with the whisk tool until fluffy, about 1 minute.
Add the arrowroot starch and beat again. Add the maple syrup and mint extract and beat until everything is combined, using a spatula to scrape down the sides as needed.
Using a spatula, mix the frosting. Frost the cooled cake immediately or transfer the frosting to the refrigerator for 10 minutes for a denser texture. Spread one-third of the frosting on top of one cake. Place the second cake on top and add the remaining frosting on top and around the sides.