Lightly coat the inside of a 4-qt slow cooker with nonstick spray. Place potatoes, shallot, garlic and butter into the slow cooker; season with salt and pepper, to taste. Without stirring, top with cauliflower and vegetable stock.
Cover and cook on low heat for 6-7 hours, or until tender.
Remove potato mixture from the slow cooker and drain excess liquid before returning to the pot. Stir in garlic herb cheese and half and half.
Using an electric mixer fitted with the paddle attachment, blend potatoes and cauliflower until light and fluffy, about 2-3 minutes. If the mixture is too thick, add more half and half as needed until desired consistency is reached. Stir in chives; season with salt and pepper, to taste.
Serve immediately.*
Notes
*This can be kept warm, stirring occasionally, up to 1 hour.