Boil potatoes. Put the potatoes in a large pot and fill the pot with enough water to cover the potatoes. Add 2 tablespoons of salt to the pot. Cover and place the pot on the stove over high heat. Bring the potatoes to a boil and let them cook for 15-20 minutes.
Mash potatoes. Drain potatoes and return pot. Add the butter and cream cheese. Use a potato masher or a hand mixer to begin mashing the potatoes. Slowly add the milk 1/4 cup at a time until you reach the consistency you want. Add salt to taste.
You can make these a day ahead and then on the morning of your dinner place them in a slow cooker with a little milk and stir them around. Turn the slow cooker to low and let them heat up, stirring every 30 minutes until they are warmed through, then turning down to warm and leaving them until you are ready to eat. If they begin to dry out just add more milk but go slow so you don’t lose the consistency you want.