Cheers, I thought of a few more:
-Using parmesan rinds in soups (pasta e fagioli is a good example) for flavor as well as saltiness.
- Similarly, using small amounts of very strongly flavored salty condiments like anchovies, fish sauce, soy sauce, chili sauces, and vegemite (umami bombs, as the foodies say). A little goes such a long way and you get heaps of flavor in addition to the salt. I use vegemite in my beef stews, swedish meatball gravy, chilis, shredded beef... It's very unlikely anyone will be able to identify there's a little vegemite or fish sauce behind the big flavor.
-Condiments in general can be big in peasant food. If you eat a fairly repetitive diet based on staples, pickles, chutneys, hot sauces, etc all go a long way to keeping things interesting and waking up the taste buds, while also preserving the garden harvest. I imagine it was a point of pride for a family to have a variety of pickles and preserves.
The Amish, for example, are known for relatively simple cooking, but also the "seven sour, seven sweet" rule - "seven different kinds of sweet condiments, jams, spreads or preserves, and seven different kinds of pickles, chow-chow or whole spiced vegetables" on the table. (Copied from some website).
-Game would definitely be prominent in peasant foods. Venison, moose, pheasant, duck, rabbit etc. I'm a huge fan of eating invasive pests myself, so for example, killing a wild boar for food is going to be an environmentally friendly act almost everywhere in the world. During a very frugal time, I shot a squirrel and we ate it. Tasted just fine (a bit stringy cuz it was an old male) and I would definitely eat it again in a pinch.
-In true frugal fashion, many peasant meals are not necessarily what we would consider the most balanced. Fueling up was the priority, so I don't think people fretted too much about going heavy on the fat or carbs. I see a lot of fat-on-starch and starch-on-starch dishes. American farmers used to eat a breakfast that would put Man vs. Food to shame, and then finish it off with homemade pie. A thick layer of fat floating on top of a soup would've often been prized, rather than scooped off. On the other hand, you might see dishes that are ridiculously healthy gut bombs, combining quite a few different whole grains, legumes, and beans in one bowl, with some herbs, greens, and spices. (I believe this is common in the middle east and north africa?) Meant to fuel a person on for a good long time at low cost.
-On a boozy note, I think sangria fits in perfectly here, as it originated as a way to doll up cheap wine. Now people pay decent money for it at restaurants and such, which is a bit crazy really! As is buying a nice bottle of wine for sangria.
Now that I think of it, sangria is very mustachian!