How to refresh a frozen bagel

Buy or make fresh bagels and store them uncut in a plastic bag with the air squeezed out of it in the freezer for up to one month. When you want to prepare a "like fresh" bagel, run it briefly under water (I used filtered water) so that the outside crust is damp but not soggy. Wrap it tightly in foil with a small vent, 1/2" long by 1/8" wide, on one side and heat in a 400°F oven (I use our toaster oven) for about 15-20 minutes, depending upon how cold your freezer is. The bagel will be as soft as it was when it originally came out of the oven and the hot oven will cause the crust to crisp through the foil. Don't let it over bake or it will be rock hard though.

I understand this is kids, and they like things just the way they like them. But preheating an oven takes time you might not have. For me I'd defrost overnight in the fridge, then in the morning split and toast them.

To get closer to fresh-baked I'd turn the oven on to a lower temperature (no more than about 150°C/300°F) and put them in almost immediately for 5--10 minutes having just brushed or flicked water on the outside. If you really want to take them out of the freezer in the morning, 10--30s (for 1 or 2, if doing more try 30s, rearrange, 30s) in the microwave before putting them in the oven will get them defrosted or well on the way.

Preheat your oven to medium heat, approx 350 F or so, pass your [uncut!] bagel quickly under running water (i.e. don't soak it), and pop it into the oven for a few minutes, like maybe 5. Bagels go through a boiling phase anyway, when they are made, so a little water contact on their outer surface won't hurt them.

I sometimes do this if I feel really fancy:

1. Put them into the microwave for a little while (like 20s at 600W for each piece). This will make them soft in the center.
2. Follow up with a couple minutes in the oven with the top heating element turned to full blast. I actually do this in the microwave as well because mine has a regular heater on top as well. I put the bagels on that riser thingy I got with the microwave, like the one you can see in the following picture:

So I actually do this all the time, because my local bagelery only makes pumpernickel on Fridays, so I buy a bunch and freeze them. In fact, I am about to do this in a few days for our traditional Christmas Morning Bagel Breakfast. After experimenting with several different approaches, this is the one I've found to work best:

Storage: As soon as they are cool, wrap each bagel in aluminum foil (I suggest also labelling what flavor it is with some tape and a sharpie), and then put up to 6 bagels in a ziplock freezer bag and freeze. The tightly wrapped foil retards freezer-burning, and is useful when you reheat.

Reheating: place the frozen bagels, in their foil, in a 300F/150C oven, which needs not be preheated. After about 15-20 minutes (20 to 30 if not preheated) the bagels should be thawed and warm. Remove from the oven, unwrap, slice and eat.

The above technique will get you as close as possible to having a fresh-from-the-baker bagel. As you can see, though, it might not be ideal for a school morning just because of the amount of time required. Don't try to speed up thawing with a hotter oven, because that will result in your bagels getting excessively dry and hard.