I love soup. I love crock pots. And I love beans. What better way to combine all three?
If you don't own a crock pot, fix this immediately. My thinking is to buy the largest one you can, at least for this --- most soups freeze very well, and I'm a big fan of making giant batches of soup and putting up portions in the freezer.
Cover the bottom of your crock pot with about one to two centimeters of dry navy beans. Peel and chop up finely one onion (I had a yellow, use whatever). Chop up a few carrots and a few stalks of celery (soup is a good use for all of the inner bits of a stalk of celery — you can save the outer bits to eat with almond butter or whatnot, and the leaves when chopped finely give the soup a bunch of flavor). Add a can of crushed tomatoes — I prefer the ones with no added salt. Pour in enough water so that you have a crock pot that is half solids, half water. Grind in some pepper, throw in a few bay leaves. I sometimes throw in some veggie sausages, cut up, sometimes not. Cover, set the crock pot to low, and come back in eight hours.
At this point, remove the bay leaves, salt to taste. It should be fairly thick, if not, take out some of the beans, mash them up, stir them back in and cook for a little longer. I'm partial to adding a dash of vinegar or lime juice to my bowl of bean soup.