Heat slow cooker on high setting.

To a large sauté pan, over low-medium heat, add onion, celery, garlic and butter. Sauté until soft and translucent. Transfer to slow cooker.

To the slow cooker, add corned beef, beef stock, sauerkraut, sea salt, caraway seed and black pepper. Cover and cook on high for 4.5 hours.

Add heavy cream and Swiss cheese and cook 1 additional hour.