If you make the custards the day before (or even earlier), as suggested in stage 2
, loosen them by adding 2 tablespoonsful of fresh cream and whisking in vigorously before pouring into the pastry case.
This tart is a fairly luxurious version, with its sweetcrust pastry case, but there's no reason you couldn't use a simpler pastry, such as plain shortcrust
If you would rather have the green layer on top, simply pour the custards into the case the other way round.
For a smoother, richer version, replace half the milk in the confectioner's custard
recipe with cream.