I can't claim to have been at all creative or unique in making this recipe. Adapting it to feed a crowd didn't really require much more than multiplication. But it is a tasty and cheap meal that feeds a lot of people. I used almost entirely organic ingredients and it cost about $4/person (which included a mixed green salad with goat cheese and blood oranges). If you're less particular about organics or downgrade the salad, it would be really cheap!
White Bean and Butternut Squash Gratin
(adapted from Russ Parson's recipe as seen at Wednesday Chef)
1 1/3 lbs thick-sliced bacon
2 large onions, chopped
1 head garlic, minced or pressed, divided into two equal portions
4 pounds dried cannellini or Great Northern beans
18 cups water
4 teaspoon salt
4 (28-ounce) cans diced tomatoes, drained
1/4 c chopped sage
12 pounds butternut squash
2 loaves day-old good quality French or Italian style bread
1 cup olive oil, plus additional for pans
Chop the bacon into rough squares. Combine the bacon, onions, half of the garlic, beans, water and salt in a large pot. Bring to a simmer, cover tightly, and cook for 2 - 2.5 hours, stirring occasionally. Add additional water if necessary.
When the beans are tender, stir in the tomatoes and sage. Stir roughly to break up some of the beans, which will thicken the liquid.
Meanwhile, peel the squash and cut it into 1/2 inch cubes. I like to use gloves for this step, as I find that cutting butternut squash does something nasty to my skin, and you have to cut a LOT of squash. Working in batches, steam the squash over a pot of rapidly boiling water for about 7-10 minutes or until tender. Set aside.
Cut the crusts off the bread and cut or tear it into rough cubes. Working in batches, process in the food processor with the remaining garlic until you have coarse crumbs. Set aside.
Prepare four 3-3.5 qt casserole dishes by brushing each with with 2 tsp of olive oil. (I only had smaller casseroles, so I just used more pans. You could use a couple of large pyrex pans instead - but don't try to go too deep - you want a good ratio of bread crumbs to filling, and for that you need lots of surface area!) Divide the butternut squash across the pans. Divide the bean mixture on top of that, using a slotted spoon. Add just enough of the liquid to cover the bottom of the pan. Stir a little to combine (the squash is fairly delicate, so be gentle). Divide the bread crumbs across all the pans. Drizzle with olive oil, about 1/4 c for each pan.
Bake in a preheated 400 degree oven for 40 minutes or until bread crumbs are nicely browned. Be sure to rotate pans from top to bottom shelf to ensure even browning. Let stand 5 minutes before serving.