Preheat oven to 350 degrees F (175 degrees C). Grease a 9-inch springform pan.
Mix almond meal, caster sugar, and coconut in a large bowl.
Beat eggs, cooled melted butter, and vanilla together with a whisk until smooth; pour into bowl with almond meal mixture and fold until smooth and batter-like. Pour the batter into the prepared pan. Sprinkle almond slices over the top of the batter.
Bake in preheated oven until the top of the cake is firm, about 40 minutes. Cool cake in pan for 10 minutes before removing to a baking rack to cool completely. Dust top of cooled cake with confectioners' sugar.