Preheat the oven to 325 degrees . Butter two 8-inch-by-2-inch round cake pans. Line with parchment and butter the parchment.
In a medium saucepan, bring 2/3 cup water to a boil. Whisk in the cocoa powder until smooth. Whisk in the butter and chocolate over low heat until melted, about 2 minutes. Remove from the heat and whisk in 1 1/2 cups granulated sugar, 2 teaspoons vanilla and 1/2 teaspoon salt. Whisk in 1 egg at a time, beating well after each addition.
In a large bowl, stir together the flour, baking powder and baking soda. Pour in the chocolate mixture until smooth. Stir in 1 packed cup coconut. Divide the batter between the pans and bake in the lower third of the oven for 35 minutes or until firm in the center. Let cool in the pans on racks for 10 minutes, then invert onto racks to cool completely.
While the cake cools, spread the almonds on a rimmed baking sheet and toast for 12 minutes; let cool.
In a saucepan, combine 3/4 cup cream, the remaining 1/4 cup granulated sugar and pinch salt and simmer, stirring, over medium heat until the sugar is dissolved, about 3 minutes. Remove from the heat and stir in the remaining 2 teaspoons vanilla and 3 packed cups coconut. When cool, fold in 1 1/2 cups almonds.
Split the cake layers to make 4 layers. Place 1 layer cut side up on a cake stand and spread with 1 cup of the coconut-almond mixture. Top with the second layer cut side down and spread with 1 cup more of the mixture. Repeat with the remaining 2 cake layers and filling, spreading the filling on the top. Cover the cake with plastic wrap and refrigerate for 4 hours to firm up.
Whip the remaining 2 1/4 cups cream with the confectioners sugar until stiff. Spread over the cake. Sprinkle the top with the remaining almonds.