By "takes more than 45 mins to make" do you mean in actual making time or cooking and making time together?Is your teacher looking for cooking skills?
Maybe a cheesecake or fruit gateau would fit the bill? Some nice little shortbread fruit towers would do, or strawberry shortcake?

A bread and butter pudd' takes 45 min's to 1 hour.
Choc sponge pudd' 45 min's to 1 hour.
Apple Charlotte same as above and fruit crumble about 45 min's.

Hi Thom,

baked apple doesn't have to take that long in the oven but doesn't get at all worried if it does get left in a low oven for 45 minutes.

Take the core out of a Bramley apple, stuff it with sultanas (they can be soaked in calvados or a similar alcaholic drink if permited, baring in mind it's at school but it doesn't matter really. The saltanas can be sprinkled with some demerara sugar or you can just sprinkle some on top.

bake in a moderate oven until tender and serve with custard.