Heat the olive oil in a large skillet and add the thinly sliced leeks. Cook for 2-3 minutes until they are tender.
Scrape the leeks into the bottom of a large slow cooker. Add the onions, carrots and garlic cloves to the slow cooker.
Top with quartered potatoes and the chicken broth.
Cook on low for up to 8 hours.
When ready to serve, turn off slow cooker and add the cream cheese in small cubes. Use an immersion blender to blend the soup to the desired consistency.