In a large bowl, beat the allulose and butter together until light and fluffy.
Add the vanilla extract and eggs, one at a time and whisk well.
Add the coconut flour, salt and baking powder and continue to whisk.
Gradually add the coconut milk until you have a smooth batter.
Pour the cake batter into the star fruit lined baking pan.
Bake for 30 -35 minutes until the cake is firm and golden. Check that it is cooked through with a toothpick.
Remove from the oven and let cool in the tin for at least 10 minutes.
Run a spatula around the outside edges of the cake to loosen it.
Place a plate over the cake tin and carefully turn it upside down.
Allow the cake to sit on the plate and remove the cake tin.
Cool the cake at room temperature before serving.