1In a large pot put the diced potatos, onion and celery, and butter, add enough water to just barely cover everything. Bring to a boil until potatos are tender. Reduce heat to very low (DO NOT DRAIN WATER OFF), add heavy cream (can use milk instead) I will add a little bit of milk to this also depending on how much broth I want. Add just a pinch of salt, pepper and garlic salt to taste. Stir and add velveeta (Depending on my mood I have used the whole brick of cheese -- I get the big box of it) stir until melted, add sour cream and stir till it melts into the soup base. To thicken it up I add the potato flakes, I really don't measure, I add and stir until I get the thickness I want. Be sure to stir in between adding the potato flakes because it will thicken quick. Serve with garlic cheese bread or a salad! Enjoy!!!