adapted from MarthaStewart.com

1 tablespoon olive oil

1 medium onion, chopped

4 carrots, thinly sliced

3 celery stalks, thinly sliced

1 tablespoon dried thyme

Salt

Pepper

1 1 /2 boxes chicken stock

1 bag yellow or green split peas, picked over and rinsed

1 1/2 cups ham, in 1/2 inch dice

In a Dutch oven, heat oil over medium heat.  Add onion, carrots, celery and thyme.  Season with salt and pepper.  Cook until vegetables begin to soften, about 8 minutes.  

Add broth and split peas.  Bring to a boil, reduce heat to medium low, and partially cover.  Simmer until peas are soft, 30 to 45 minutes.

With an immersion blender, puree half of the soup right in the pot.  Add ham cubes and simmer until heated through.  If necessary, thin with additional water or stock.  Season with salt and pepper.