I'd say bake it then warm it up
I like you, will NOT leave the stove (on) unattended for more then 15 mins(in the house) ever regardless.
Not sure you cold par bake it either?
I know it takes my "lasagne" 20mins to become editable from the molten lava state

Hrmmm this gives me an idea @:-) ... slow cooker Pastitsio
I know the lasagne recipe I tried was pretty good in the slow cooker.