Cook those onions to caramelize, chop and freeze in ice cube trays. Pop amount needed into your pot of....easy, plus no waste of an unused jar or a canning lid!! Those rascals ain't cheap now!
Pressure canning isn't hard, just some tiny rules to acknowledge. Jump on in there
@Trying2keepitReal. The initial cost of the canner should be considered as a good investment for many years! Not to mention how much you can preserve with it. Saves freezer space. Cans ready to heat and eat...faster than thawing. Ketchup is easy just LOTS of tomato and time

. Grow a few extra plants.