If the potatoes are not covered by the broth add water to the slow cooker until the potatoes are just submerged.
water
Put the lid on the slow cooker and set the it on high. Let it cook on high for about 4 hours, then reduce the setting to low. Let the soup continue to cook on low for 2-4 hours, until you are ready to eat.
About 30 minutes before you are ready to serve the soup stir in the cream and turn the slow cooker to warm. Use a potato masher to mash about half of the potatoes, leaving some to give it a chunky texture. If you prefer a smoother texture you can use an immersion blender to blend all the potatoes.
1 cup heavy cream
Let the soup sit on warm for about 30 minutes. Right before serving stir in the cheese.