Wash sweet potatoes and cut in half width-wise. Place in an 8-quart slow cooker with 1/2 inch water in the bottom (about 1 cup or so). Cutting the sweet potatoes in half means less cooking time, but you can keep them whole and cook them a bit longer to avoid dark spots from oxidation in your sweet potatoes.
Cook on high for about 2-1/2 hours (longer if left whole) or until the sweet potatoes are tender and softened.
Remove the sweet potatoes from the slow cooker and remove the peel. The skin should come off easily.
Place the cooked and peeled sweet potatoes in a large bowl with the other ingredients and using a hand mixer, blend the sweet potatoes until everything is mixed well and there are no lumps.
Serve immediately or return to the slow cooker on low setting to keep warm until your other dishes are finished cooking.
Enjoy!
Notes
If you can't find garlic egg-free mayo, you can use regular egg-free may and add some garlic powder