Following is an easy, sustainable way to make it while reducing your garbage footprint in the ecology.
Step 1: Ingredients And Making Your Freezer More Efficient
Keep a large food safe plastic bowl with a lid in your freezer (a plastic freezer bag works too), and every time you prepare vegetables, throw the ends, peelings, onion skins and leftover bits in the bowl. When you have more of an herb than you can use before it goes bad, throw that in, too!
DONT throw in anything rotten, but do throw in anything that getting to old to use, but not actually rotten yet. The following list are some of the veggie bits I habitually throw in, and I'll also include a few thing that don't really work as a separate list:
Carrot ends and peelings
Scallion ends - including the root bits
Beet greens and peelings
Carrot greens (if you are of the school that eats them, not everyone is)
Stem ends of tomatoes
Onion ends and skins
Broccoli stems and leaves (also the trimmed yellowed florets if you left it in the fridge too long)
String bean strings and ends
Garlic paper and ends - also old garlic that is getting hard and yellowed but not when it gets powdery and mildewed.
Cucumber peelings IF they aren't waxed.
Lettuce stems and discarded leaves
Squash ends and rind if you peel that (zucchini, yellow, acorn, all of it!)
Leftover cilantro, dill, tarragon, basil, marjoram -any herbs
Leek trimming and ends
Pea pods if you shell your own
Parsnip ends and peels
Red or yellow pepper trimmings
Basically, the trimming, peelings and ends of nearly all vegetables.
Brassicas - cauliflower, Brussell sprouts and cabbage are not good, they add a strong, unpleasant odor and taste.
Anything that has gotten slimy or rotten - the idea is to toss it in the freezer bowl before it goes bad, but it's okay to use it just before it goes bad, when it's wilted, dried out, or yellowing.
Just keep throwing the trimmings into the bowl until it's full.