The other way that I preserve food is in the freezer. I often cook large batches of things and freeze them for later use. Most commonly I think we think in terms of meals when we talk about cooking in large batches, but I also do the same with ingredients for future meals.
One of the easiest "frozen assets" is stale bread. I freeze the odds and ends of the bread we don't quite finish, usually, the heals and small hunks of french bread. Once I have a large zip-top bag of bits and pieces I pull out the food processor and turn it all into breadcrumbs. These breadcrumbs go back into the freezer and are later added to meatloaf, meatballs, top mac'n'cheese. The same crumbs can be toasted to use for breading on meats, cheeses, or vegetables.
Another easily frozen asset is to take veggie scraps like carrot ends, onion peals, cilantro stems, etc and drop them in a freezer back. When the bag gets full make vegetable stock. Once you have a great veggie make, freeze in one or two cup portions to use in future dishes.
Our crockpot gets a workout when I cook for the freezer. Chicken stock happens often after we cook a whole chicken for a meal, like this Fauxtisserie Chicken from Our Best Bites. Once we've eaten the chicken and picked it clean, I put the picked carcass into the crockpot with carrots, celery, onion, and some herbs. Top with enough water to cover and cook for 8 to 10 hours on low. I strain the broth and put it into 2-cup containers and freezer for later.
Onions are so easy to carmelize in the crockpot. I use this recipe from Kitchn and they turn out perfect every time. Wondering what I do with them after I cook them? I freeze them. I usually put them into my vintage muffin tins to flash freeze them into 1/2 cup portions for recipes later. I put them in chili, burgers, meatloaf, soups, and stews. You could also use them for a quick French Onion soup.
These are just a few of the things I make for the freezer. I realize the freeze isn't always the best method of preservation, but if you cycle things through, much like the working pantry we talked about last week you won't lose things for a lifetime in there.
I also highly recommend a vac sealing machine for freezing as well. We use ours mostly for freezing cuts of meat, but it can be used for freezing most of the things we talked about above. I'm not sure I would freeze broth this way, but breadcrumbs, onions, and leftover chicken would be great things to vac seal and freeze for later.