Preheat the oven to 350°F (175°C). Grease and flour an 8-inch round cake pan.

Cream the softened butter and granulated sugar until light and fluffy. Add the eggs one at a time, mixing well after each addition, then stir in vanilla.

In a separate bowl, combine the flour, baking powder, and salt. Add the dry ingredients to the creamed mixture alternately with the milk, beginning and ending with flour. Mix just until combined.

Pour the batter into the prepared pan and smooth the top. Bake for 25 to 30 minutes, until a toothpick inserted in the center comes out clean.

Cool the cake in the pan for 10 minutes, then transfer to a wire rack and cool completely.

For the mousse, bloom the gelatin in 3 tablespoons cold water for about 5 minutes.

Combine the coconut cream and powdered sugar in a saucepan. Heat over low heat, stirring until the sugar dissolves. Do not boil. Remove from heat and stir in the bloomed gelatin until completely dissolved.

In a separate bowl, whip the heavy cream to soft peaks.

Gently fold the coconut mixture into the whipped cream. Fold in the drained crushed pineapple until evenly combined.

Place the cooled sponge back in the cake pan. Pour the coconut mousse over the sponge and spread evenly. Refrigerate for at least 4 hours, until set.

For the glaze, bloom the second packet of gelatin in the remaining 3 tablespoons cold water for about 5 minutes.

Combine the pineapple juice and granulated sugar in a saucepan. Heat over medium heat, stirring until the sugar dissolves. Remove from heat and stir in the bloomed gelatin until completely dissolved. Let the glaze cool slightly.

Pour the slightly cooled glaze over the set mousse and spread from edge to edge. Refrigerate for another hour, until the glaze is set.

Slice into 12 portions and serve chilled. Garnish with toasted coconut flakes or fresh pineapple slices if desired.