I used to make a recipe similar to Ely's - but with 100% all bran. We'd put dried cranberries, etc. in instead of raisins (2 of the kids hated raisins!). They really DO keep well for that long of a time. I am sure you could easily adapt Elly's recipe to use the cereals your mother used to use. All my recipes are still in boxes - from a move. Just got stuff out of storage and someday I'll get to these things.
We used to make 1 or 2 at a time in the microwave (I didn't have micro muffin cups - so we cut down foam cups and inserted a paper cupcake liner - forget how long they took - but the kids LOVED doing that and even my husband did.) We liked them better in the oven - nicer crust, etc. But sometimes - time was important.