Preheat your oven to 350°F (175°C) and grease an 8-inch round cake pan.

In a large mixing bowl, cream softened butter and granulated sugar together until fluffy, about 3-4 minutes.

Gradually add eggs one at a time, mixing well after each addition.

In another bowl, whisk together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.

Alternate adding the dry mixture and coconut milk to the wet mixture, stirring until just combined.

Fold in the lime zest, pour into the prepared pan, and bake for 25-30 minutes until a toothpick comes out clean.

Allow the cake to cool completely on a wire rack.

While the cake cools, bloom the unflavored gelatin powder in cold water for about 5 minutes.

Gently heat the bloomed gelatin over low heat until dissolved, stirring constantly.

In a separate bowl, whip the heavy cream until soft peaks form, then gradually add powdered sugar, vanilla extract, and lime juice.

Carefully fold melted gelatin and coconut cream into the whipped cream mixture until smooth.

Once cooled, slice the cake in half horizontally to create two layers.

Place the bottom layer on a plate and spread half of the coconut lime mousse over it.

Gently place the top layer back on and smooth the remaining mousse on top.

Refrigerate for at least 4 hours.

Before serving, sprinkle with toasted coconut flakes and place top with lime slices.