Stuff your Excelsior or Excalibur or solar dehydrator with them.
When they're brittle, fish them out and strip dry matter from midribs. Clean up and crumble to desired consistency. Dry can (bake) in jars and open to use as needed. Good for up to five years in our experience.
Kale, collards, chard, beets, spinach, cabbage, broccoli, cauliflower, dandelions, false dandelions, lamb's quarters, turnip, arugula, garlic, onions, young bean leaves or knotweed leaves, chicory, plantain, nettles, maple and lilac flowers, nasturtiums, kohlrabi, lettuce, and tatsoi, along with herbs to taste can all be included in this. The more variety, the better nutrition, and they all taste about the same in this form.
You could live a long time, comparatively speaking, if shut in by a pandemic, for example, on just twenty pounds of dried veggie crumbly and a hundred pounds of rice. Be sure you have also secured a supply of water.
You could, with a little acquired knowledge and some persistence, do this entirely with foraged weeds even if you have no garden.
Use in breads, soups, frittatas, quiches, on meats, on potatoes, in eggs, power drinks, hot cereals, salads, wilted salads, stir fries, etc. Also can be added to feeds such as poultry feeds.
Caveat: spinach and amaranths contain a lot of oxalic acid and so there are those who should not consume them in quantity.