Oh, YUM! I love liver, both chicken and calves, and Chocolate pretty much described how Mom did it (except she used margarine rather than bacon).
Mom also made a meal we called "lizards and gizzards". She'd save all the necks, livers, hearts, and gizzards from chickens (which we ate a lot of as it was a bargain when I was young). She'd boil them, and when tender, would strain out the meat, then boil egg noodles in the broth. At the last minute she'd throw in some mixed veggies, toss it all together, and it was one of my favorite meals.
As far as vegans getting protein, it really isn't that hard, but you do have to pay attention a little more than people who eat a bit of everything do. I once did an interview with a woman who came from a 3-generations vegetarian family, and she, her children, and her father were all vegans. No matter what you tell me it is more work to get the nutrition, but even so, it's mostly in the knowledge. I joked with her that I'm a confirmed omnivore, but when she threw vegan buffets, my dishes were always the hit, and never had those little screw ups you can do if you do not understand vegan. No worchestershire sauce (contains anchovy). No honey (a confirmed vegan not only does not eat animals, they don't eat animal products -- milk, honey, etc -- and do not wear leather). So it can be a chore. Calcium can also be a problem, but is easier to solve -- lots of dark green.
To me this turns eating into a chore, I could never do it. Don't think my vegan freinds are healthier than me. But differences are what make life fun.