"Freezer cooking" refers to the practice of preparing and assembling meals in advance and then freezing them for later use. It helps save time and effort as you can cook multiple meals at once and have them readily available whenever you need them.
I am a big fan of anything that's all in one pan that can be thrown in the oven - this is going on my next big freezer cooking day's meal plan. (thekitchenismyplayground.com)