Cut the potatoes into like sized pieces so they all cook at the same rate. Cook the potatoes in large pot of boiling salted water until they are tender, about 20 to 30 minutes.
Drain the potatoes and return to the dry pot. Shake over low heat for about 1 minute. This helps make the potatoes fluffy as it whisks off excess moisture.
Mash the potatoes until there are no lumps
Heat cream, milk and butter in a small saucepan over medium until just about to simmer. Reduce heat to low and keep warm until ready to add to potatoes.
(If you have a potato ricer or mill, pass the potatoes through into a bowl. If you don’t have a food mill you can mash the potatoes with a potato masher), slowly add cream mixture while tossing gently, season with sea salt and pepper and mix in sour cream.
Take the potatoes out of the refrigerator about 3 1/2 hours before serving time. Stir the potato mixture well. Remove the potatoes from the dish and place it in a 4- or 5-quart crockpot. Cover and cook on low heat for 3 to 4 hours, stirring once or twice.
add more melted butter, sour cream or milk if you want a softer consistency. The potatoes can be held in the slow cooker an additional 30 minutes or more on low. Or turn the crockpot to "keep warm" for another hour or two.
*Melissa’s Dutch Yellow Potatoes can be found at Gelsons, Bristol Farms and Lazy Acres or order from their website (link below).