Instead of having to put actual dishes in the freezer, another option is to line the dish in question with heavy duty aluminum foil.
Put the sheets both lengthwise and crosswise with plenty of overhang on each side. Have one extra layer of alumimum foil going one of the directions - you'll see why.
Layer or otherwise fill the dish with food as normal.
Partially cook, if recipe calls for that - some lasagna recipes do...
After dish is cool enough, flash freeze it - a.k.a. put it in the freezer for about 30 minutes.
At this point you should be able to tightly fold the extra layer of aluminum foil over the top of the food without it sticking to any gooey cheese you may have on top. Loosely fold the remaining foil over so it is not in the way - but you are going to want to use these as "handles" later.
Put it back in the freezer until good and frozen. 8 hours? Overnight?
Take the dish out of the freezer and use the still loose pieces of aluminum foil to lift the now frozen block of food out of the dish.
Wrap tightly in aluminum foil. Wrap tightly in plastic wrap or insert into heavy duty freezer bag. Label bag with what dish you took it out of, oven temp, baking instructions, etc.
When the time comes to bake it, remove bag and/or plastic wrap, pop into appropriate dish, fold back/tear off extra alumn foil as desired and bake!
This option does not limit you to either tying up dishes in the freezer or contantly purchasing the throw away type of aluminum pans. I love it!
