Preheat the oven to 350 degrees. Lightly grease two 9-inch round cake pans with coconut oil and line the bottoms with baking mats or parchment paper.
In a large bowl, whisk together gluten-free flour, sugar, cacao, baking powder, baking soda, and sea salt. In a separate bowl, whisk together coconut milk, oil, vinegar, and vanilla. Pour the wet mixture into the dry mixture and then add the hot water. Mix until combined, do not over mix.
Fill each prepared cake pan with an even amount of batter. Bake for 15 minutes, then rotate and bake for an additional 15 minutes. Or until a toothpick comes out clean with only a few crumbs.Let the cakes cool for 30-60 minutes, until completely cooled.
Meanwhile, melt the vegan butter and chocolate over medium-low heat. Whisk frequently until smooth. Transfer to a bowl and add in the powdered sugar, vanilla, and almond milk. Beat with a hand mixer until fluffy and spreadable.
Loosen each cake from the pan by running a knife around the edges and then transfer the first cake onto a cake stand or serving plate. Top with frosting. Remove the next cake and place directly on top of the first frosted cake. Frost the top and sides if desired. Garnish with chocolate shavings.