I don't use jelly in my trifle.
I use madeira cake crumbled up as the base, and the juice from a tin of mandarin orange segments with some Marsala sweet wine. Then I put the mandarins and a tin of fruit cocktail on top, and a layer of Birds custard (made from custard powder) about 1 pint. I usually do this the Christmas eve, then when it has a nice skin, the next day whip the cream to finish it off. I reserve a few segments of mandarin orange and bits of cherry from the fruit cocktail to decorate it. Non alcoholic version, use the juice from the tinned fruit. (I always used 'tinned in juice' rather than syrup. You could get around 8 normal portions or 6 greedy ones from this. It is our treat for Christmas day supper after cheese and pates on crackers.
One of the easiest trifles is one of Nigel Slaters, you make it with raspberries, sponge cake or swiss roll and a mixture of ready made custard and cream, but you can use that posh vanilla custard with cream in it from the supermarket chilled cabinet which is just as good, and defrosted frozen rasps. This isn't intended to be a trifle of strict layers. I think you could use raspberry or raspberry and apple fruit juice instead of the wine if it needs to be non alcoholic. This is meant to be a late summer trifle, but frozen raspberries are so good it's nice to have them out of season for a special occasion.
This is the recipe for 6 from his book Appetite.
A Really Great Trifle.
1 swiss roll or 200g sponge cake
sweet wine 125 ml
double cream 300ml
custard 250ml ready made bought
raspberries approx 2 good handfuls plus some to scatter on top
Crumble the sponge into rough lumps or slice swiss roll, then soak with wine. Whisk the cream slowly until it will stand in soft peaks but able to blob off the spoon. Stir half of this gently into the custard. Whizz the raspberries in a blender or mash with a fork to almost pouring consistency; add a drop of water if not, and drizzle most of the puree over the cake base. Then spoon the custard /cream mixture over the cake, letting it merge with the raspberries. Spoon the remaining cream over the top, scatter remaining rasps and drizzle rest of the puree.