Chicken and yam (or sweet potato) soup

This is great soup for cold weather, it's nice and spicy and really yummy. It's just a basic recipe, so mess with it a lot, but these are tried and true ingredients. I always make the soup the day after I roast a chicken, so I save about a breast's worth of chicken and make the stock out of the bones.

Serves 4 (big bowls of soup)

1 onion, finely chopped
6 or 7 cloves of garlic (plus or minus to taste), finely chopped
2 or 3 tablespoons ginger, minced
2 medium sized yams or sweet potatoes (or other tubers, carrots, whatever) cut into half inch or so squares
32 oz chicken stock
about a breast worth of chicken chopped
4 or so tablespoons thai-style sweet chili sauce

Saute onion, garlic, ginger until flavor comes out and onion is translucent
Add yams, saute for a few minutes
Add stock, bring to boil then cover and reduce heat
Simmer for 20 -30 minutes, until yams are soft
Cool off a bit if you want to throw it in the blender (depending on how smooth you like your soup, I generally just run a hand masher through it at this stage)
Warm soup again (if needed)
Add chicken and sweet chili sauce, heat through

It's very filling, but is really good with chewy bread.

Variations:
1. A slug of heavy cream at the end turns it into "cream of.... soup" and is yummy
2. Chopped scallions are nice in it
3. Add chopped lemongrass when you put in the yams. Instead of heavy cream use coconut cream and add cilantro at the end
4. Ramp up the heat with chili peppers at the start.