Emergency Food for my dwarves

Gathering Herbs is the easiest way. If you're in a desert / tundra, breach the caverns and herbalize from there.

If you have extra cats, you may consider slaughtering them as well.

Brewing would have left seeds behind. Press 'z' to go to your fort overview and then get into the kitchen menu. Enable the cooking of whichever seeds you have most of, or that you don't have any plans to plant in your farms. Your cook will turn them into prepared meals. Then keep an eye on your seed stocks as you don't want your cook to get overexcited and cook all the seeds too.

Some people frown upon it, but you can also enable cooking of booze.