Start this recipe by making the syrup. Place all the ingredients except the alcohol in a saucepan with 250ml water and cook together for 5-10 minutes. Remove off the , add in the liqueur and allow to cool down completely. To make the cream filling, mix together the whipped cream, cold custard, white chocolate and orange zest. Divide into 2 bowls. Blitz half the defrosted berries and mix into half of the cream filling. To put the trifles, place a few cubes of sponge in the bottom of the trifle jars. Spoon over some of the prepared syrup to soak well. Next, spoon over the remaining ½ berries, ½ of the walnuts followed by the white cream filling. Add another layer of sponge and soak again with the liqueur. Next, spoon over the berry cream filling followed by the remaining walnuts and white chocolate chips. Place into the fridge and chill for a few hours before serving.