I found these in the local Walmart yesterday and my sweet tooth started humming:

http://www.heinz.co.uk/ourfood/pasta/tas...ed-dick-pudding

Canned goods are heavy but you don't have the same weight concerns in your trunk as you do on foot. I also like that canned goods are crush resistant. That can come in handy in the trunk.

Freezing is an issue here though, so I don't keep canned goods in the vehicles regularly. I take them for roadtrips but usually keep a box of cliff bars and peanut m&Ms in my trunk kit, because they're more versatile.