We apparently have two other pasta e fagioli soup on this site, and it's interesting now not-similar both of those versions are to each other or to this one, which is from How to Cook Everything. It could definitely be modified in 8000 different ways.
5 T olive oil
1 large onion, chopped
2 t minced garlic
2 sprigs fresh rosemary or 1 t dried
3 c drained beans of any kind [I used one can of dark-red kidney and one can of cannelini]
2 c cored, peeled, seeded, diced tomatoes [Bittman says canned are fine and use the juice; I only had crused and used one big can, which made the soup have a tomato base, pretty much]
6 to 8 cups stock or water
1/2 lb tubettini or other small pasta
1/2 c minced fresh parsley
1/2 c Parmesan [however much you have is fine; this is just for on top]
Place 4 T of olive oil into a large, deep saucepan or casserole and turn the heat to medium. A minute later, add the onion and half the garlic [I threw it all in at this point]. Cok until the onion softens, stirring occaionsally, about 5 minutes.
Add the rosemary, beans and tomatoes and cook, stirring and mashing tomatoes with your spoon, until the mixture is warm and the tomatoes begin to break down, about 10 minutes.
Add 6 cups of stock or water and a good amount of salt and pepper. Raise the heat to medium-high and bring to a boil. Turn the heat to medium-low and simmer for 10 minutes, stirring occasionally.
Add the pasta, along with additional stock or water if necessary [will probably be necessary]. Simmer until pasta is nearly tender, 10 minutes or so. Add half the parsley and the remaining garlic and cook another 5 minutes, until pasta is done but not mushy.
Sprinkle with remaining parsley and drizzle with the remaining olive oil [not sure why one would do this...]. Serve, passing the cheese at the table.