Spread a layer of the cooled down coconut custard over your first cake layer. Make sure that the coconut custard is cooled down but not straight from the fridge. Just being room temperature will work. If you place it in the fridge it might be hard to spread it over the cake.
Cake will store well in your fridge for up to 4 days.
*You can toast the coconut by simply placing a layer of dried coconut flakes on a non stick frying pan. Place over medium heat, and cook coconut for a few minutes until it's golden brown. Make sure to stir and flip the coconut flakes constantly to brown evenly.