For the coconut custard, whisk the egg yolks and sugar together in a bowl until pale and thickened. Add the flour and mix well.
Place the coconut milk and vanilla seeds into a saucepan over a low heat and slowly bring to the boil, then remove from the heat.
Add the coconut milk mixture to the egg mixture gradually, whisking well, then, once completely combined, return the mixture to the saucepan. Place over a medium heat and bring back to the boil, then reduce the heat and simmer for five minutes, stirring constantly. Remove from the heat and pour into a clean bowl, cover with cling film and chill.
When the coconut custard is cold add the whipped cream and fold into the custard.
Meanwhile for the trifle base, place the strawberries into a bowl, cover with icing sugar and orange liqueur and place into the fridge to marinate and chill for one hour.
Break the cake up into chunks and place into the bottom of a large glass serving bowl (or divide into six glasses or little bowls for individual portions). Drizzle some orange liqueur onto the cake.
Place the marinated strawberries on top of the cake pieces, then add the kiwi slices.
Place the jam into a bowl and add a little hot water to soften it, then pour it over the cake and fruit.
Spoon all of the chilled coconut custard mixture onto the trifle base. Return the bowl to the fridge to set for at least two hours - preferably overnight.
For the topping, whip cream the cream until stiff peaks form when the whisk is removed. Add the mascarpone and mix together gently, then spoon the mixture over the custard in the bowl.
Finally, sprinkle the toasted coconut over the top and serve.