Well, first I get a pig foot, with ankle, chopped into several pieces, boiled for a few minutes to get the gunk out, then into a pot with the scraps from 5 or chickens(giblets, carcasses, wing tips, etc.) and get that simmering, de-scumming for about 30 minutes. Meanwhile I'm roasting a head of garlic, a sliced onion, and a 2 inch chunk of galangal, sliced, for about an hour. When the veggies are roasted they go into the pot and the whole shebang simmers for 5 or 6 hours. That gets strained and the broth chilled so that the bulk of the fat can be lifted off. The last batch resulted in around 6 quarts of soup base.
When I'm ready to make some soup I start with a quart of the base and add a bruised stalk of lemon grass, 6 kaffir lime leaves, a large clove of crushed garlic, and some slices of fresh galangal. I simmer this fro another hour and add some squirts of nam pla and lime juice.
The noodles get boiled up and put into bowls while the strained soup poaches the veggies, in this case baby bok choy, and a boiled egg is set on the noodles with what ever protein is up for grabs. The contents of the pot are ladles onto the bowls and there ya go! I like some togarashi and green onions on top, sometimes sesame seeds/oil. Whatever is in the fridge is fair game for this. It can be varied endlessly.